bluuebunny/crossref_metadata_2025 huggingface dataset:
Modelling of Voids Closure in the Diffusion Bonding Process
Authors: Alegria J. , Miranda R.M. , Gómez de Salazar José Maria , Fernandes A.A.
Published: March 2009

Diffusion bonding is a solid-state welding process that allows the joining of similar or
dissimilar heterogeneous materials preventing the weldability problems associated to fusion
welding. Modelling of this process has been attempted by several authors like Hill and Wallach [1].
These authors considered that the plastic deformation between two surfaces in contact is one of the
most important mechanisms involved in the process. This paper reports the results of diffusion
bonding of 1045 steel. Modelling of the process was done using Hill and Wallach [1] parameters to
define the surface roughness condition. During preparation for diffusion bonding a series of long
parallel ridges, typically with 0.2 to 2 µm high (roughness asperity height) and 30-70 µm width
(roughness wavelength) were produced. The initial contact of the asperities on the prepared surfaces
created a series of voids with an elliptical shape (infinitely long parallel cylinders with elliptical
cross-section). During the diffusion bonding process the shape of the voids changes, becoming
smaller, mainly due to the pressure application. Since this is a diffusion controlled process, the use
of temperature promotes the deformation process. A model using Finite Element Analysis coupled
to a commercial software was developed considering two surfaces, containing an half void, which
were brought into contact. The first model was developed with only one elliptical void with two
different widths (30 and 70 µm) and 2 µm high. In this model enough pressure was applied to close
completely the void. The second model considered three voids placed together to simulate the voids
continuity. Finite Element Analysis was developed considering that initial contact between surfaces
with asperities creates a series of voids with elliptical shape. In the initial stage of the process, the
pressure applied changes the shape of the voids due to plastic deformation increasing the contact
area. Microstructures were investigated.
Ceramic Properties of Alumina and Alumina-Mullite Pressed Bodies Based on Al-Rich Anodising Sludge
Authors: Ribeiro M.J. , Labrincha Joao A.
Published: March 2009

Alumina and alumina-mullite based refractory ceramic materials were produced from
formulations based on an industrial Al-rich sludge derived from the wastewater treatment of the
aluminium anodising process. Other ceramic raw materials like diatomite was also added, which
can be consider as a by-product. Cylindrical samples processed by uniaxial dry pressing were
sintered at different temperatures (between 1400-1650°C, 1 hour soaking) to study the ceramic
properties evolution. The performance of fired materials was evaluated (firing shrinkage, water
absorption, bending strength, thermal expansion coefficient, refractoriness and SEM microstructure)
and demonstrated that optimal properties were obtained at 1650°C for alumina and 1450°C for
alumina-mullite.
Acid Leaching of Leather Tanning Sludges: Metals Behaviour
Authors: Oliveira Paula C. , Rosa M.C. , Gonçalves Lucinda , Trancoso Maria A. , Nogueira Carlos A.
Published: March 2009

Sludges generated in leather tanning processing are very complex wastes with potential
deleterious effect on the environment and its management constitutes a high cost for the companies.
In this work, sludges from a Portuguese tanning company were characterized and leached with acid
solutions in order to evaluate the metals removal yields. The sludges contain, as main metals, 15%
Ca, 5% Fe and 2.2 % Cr, in a dry basis. Other minor elements namely Al, Ti, Zn, Pb and Cu were
also detected. The leaching experiments were carried out with two types of acids – hydrochloric and
sulfuric – and the effects of the reaction time, temperature and leachant concentration were
evaluated. The reaction conditions strongly affected the chromium leaching yields, being
temperature and acid concentration highly significant (confidence level above 99.9%). About 90%
of Cr was leached using the higher levels of the factors (4h, 80°C and 2M H+, with both acids).
Concerning the other major metals, iron leaching was very efficient (yields usually above 90%)
whatever the conditions tested while calcium behaviour was quite different, depending on the type
of acid used for the same H+ concentration: H2SO4 leaching efficiency was generally lower than
HCl, probably due to the formation of less soluble calcium sulfate. The maximum calcium removal
achieved was near 75%. The leaching process developed can be useful not only as a
decontamination step of the tanning sludges, but also as a process for metals recovery to be
potentially applied in an integrated recycling system, where several metal wastes from different
sources could be processed.
Leaching Studies of Spent Zinc-Manganese Alkaline Batteries with Sulphuric Acid
Authors: Guerra R.N.G. , Nogueira Carlos A. , Margarido Fernanda
Published: March 2009

The hydrometallurgical processing of metal bearing residues is one of the established
routes envisaging metals recovery. In these processes, the leaching operation plays a central role as
allows the solubilization of metals for further separation and recovery as pure products. This route
can be applied to spent domestic batteries recycling, which studies on sulphuric acid leaching of
spent alkaline batteries are reported in this paper. Material samples used in the trials were prepared
concerning the real proportion of the most common sizes and shapes of batteries found in the usual
stream of this type of wastes. The research involved the evaluation of some factors which affect
leaching yields namely temperature, reaction time and stirring speed, through a two-level factorial
design methodology and analysis of variance. In this study, other factors related with leachant
concentration and stoichiometry were maintained constant. Zinc leaching yields were generally high
and even near 100% when the high levels of the variables were used, meaning that zinc oxides
present in the electrodes are very reactive to acid leachant. The variables had all positive effects
being temperature the most significant factor (confidence level 99%) while the other factors were
less significant (98.8% for time and 95% for stirring speed). Concerning manganese, leaching yields
obtained were more dependent from the factors, being also positive and varying from 11% (for low
levels of factors combination) to 89% (for high levels of factors combination). Temperature and
time were highly significant (confidence levels above 99.9%) while stirring speed was less
significant (97%). Contamination of leach liquors with iron was also evaluated since it is an
impurity which requires special attention during the process development. For the higher levels of
the factors (t = 1 h, T=80°C and ω=400 rpm) the final solution contained 10 g/L Zn, 15 g/L Mn and
3.2 g/L Fe. The removal of the iron from the solution is a necessary step prior to the separation and
recovery of zinc and manganese.
Development of Structural Ceramics from Fly Ash and Shale
Authors: Monteiro Regina da Conceição Corredeira , Lima M.M.R.A. , Clemente C.S.
Published: March 2009

The possibility of using fly ash and shale as alternative raw materials for the production
of structural ceramics was investigated. Fly ash is a by-product from coal-burning power plants, and
shale is a sedimentary rock that if ground finely enough can exhibit a clay-like plasticity. Ceramic
samples containing 10-50 wt% fly ash were formed from mechanical mixing of both kinds of
powders that were packed and sintered in the temperature range 950-1200°C. It was verified that
powders with larger fly ash content exhibited lower packing density resulting in compacts with a
lower sintered density. Although an increase in fly ash content was associated to a larger presence of
porosity in the sintered samples, as confirmed by microstructural analysis, all studied compositions
when sintered at the highest temperatures exhibited satisfactory values for water absorption
(< 10%), for flexural strength (20-64 MPa) and for hardness (20-30 GPa) indicating that they have
potential to be applied in the production of structural ceramics.
Development of Monolithic Materials with and without a Binder with Carbon Molecular Sieving Properties
Authors: Valente Nabais J.M. , Padre-Eterno A. , Carrott Peter J.M. , Ribeiro Carrott Manuela M.L. , Galacho Cristina
Published: March 2009

In this work we studied the production of activated carbon fibres in monolith shape from
a commercial textile acrylic fibre. The monoliths were produced with and without a binder. The
binders tested were phenolic resin, polystyrene, polymethylmethacrylate and clay. We also tested
the influence of using a solvent. The SEM analysis indicates that the monoliths are made of
filaments that can be considered activated carbon fibres. The type of binder influences the fibre
orientation, degradation and materials shrinkage, the worst results being obtained from the use of
polymethylmethacrylate and polystyrene in toluene. The best results are obtained when the
monoliths were produced only with acrylic fibre and with phenolic resin as binder. The use of
solvents has opposite effects for the carbonised and activated samples. In the former case it seems
that the water can be fibre protective but during activation the presence of water leads to an increase
in the monolith’s burn-off. The methodology used leads to the formation of excellent samples for
performing the gas separations O2/N2
and CO2/CH4. Some samples show maximum selectivity for
the referred separations because N2
and CH4
are almost totally excluded from the porous structure
which indicates a good potential to be utilised in PSA systems or for natural gas purification. The
adsorption capacity is very dependent on the conditions used. Nevertheless, the best sample has a
considerably high adsorption capacity (32cm3g-1 for CO2
and 4cm3g-1 for O2, after 200s contact
time).
Structure and Electrochemical Characterization of Ni+W+Si Composite Coatings in an Alkaline Solution
Authors: Popczyk Magdalena , Budniok Antoni , Łągiewka Eugeniusz
Published: March 2009

Ni+W+Si composite coatings were prepared by nickel deposition from a bath containing
suspension of tungsten and silicon powders. These coatings were obtained under galvanostatic
conditions, at the current density of jdep. = 0.100 A cm-2 and at the temperature of 338 K. A scanning
electron microscope was used for surface morphology characterization of the coatings. Chemical
composition of the coatings was determined by EDS method and phase composition investigations
were conducted by X-ray diffraction. Thermal treatment of obtained coatings was conducted in the
air and nitrogen atmosphere. Electrochemical corrosion resistance investigations were carried out in
the 5 M KOH, using potentiodynamic method. It was found that Ni+W+Si coatings after thermal
treatment in the air are more corrosion resistant in alkaline solution than Ni+W+Si coatings after
thermal treatment in the nitrogen atmosphere and as-deposited coatings. The main reason of this is
presence of new phases, in particular NiWO4 and SiO2.
The Effect of Dual-Suctioning System on the Bacterial Contamination of Bone Debris Collected in the Oral Cavity during Dental Implant Surgery: Microbial Analysis
Authors: Kim Young Kyun , Park Kyoung Un , Yun Pil Young , Kim Su Gwan
Published: March 2009

There have been many clinical trials to collect bone debris utilizing special equipment
and to apply in the bone graft procedure simultaneously. Collected bone debris (CBD) may be
contaminated by bacteria. This may lead to iatrogenic contamination of recipient sites by grafted
bone debris. The purpose of this study was to evaluate the effect of strict suction protocol on the
levels of bacterial contamination. Total 41 patients (21 male and 20 female patients) with a mean
age of 48.97 were selected in this study. They were randomly divided into two groups in this study.
One group consisted of a single-suctioning group, while the other was dual-suctioning group. A
bone collecting device was used to collect bone specimens during drilling. Samples were obtained
and cultures of CBD were performed. Among the 41 samples of cultured bone debris, only 16
samples yielded viable microorganisms. Microorganisms were detected in the 54.5% (12/22) of
single-suctioning group, and in 21.1% (4/19) of dual-suctioning group (p=0.03). The majority of
microorganisms were Gram positive cocci. It was shown that erythromycin and clindamycin were
more effective than penicillin in the antibiotics sensitivity test.
It was concluded that the use of strict suction protocol could reduce the bacterial contamination.
Internal Expansive Reactions in Concrete - Prevention of its Occurrence
Authors: Cristino A.F. , Melo Jorge M.E. , Salta Manuela M. , Silva António Santos
Published: March 2009

This work concerns with the study of coatings to inhibit the ingress of water and also the
use of lithium nitrate to modify the swelling properties of the ASR reaction products. In order to
accomplish these objectives concrete samples extracted from a Portuguese structure affected by
internal expansive reactions were treated with six different coatings and subjected to natural and
accelerated environments. In order to study the modifications produced by lithium nitrate in the
expansive properties of ASR products, different test conditions were used namely the application of
lithium by immersion and electrical migration. In this work we present the results of the application
of these treatments namely by the evaluation of the mechanical, physical, microstructural and
electrical properties.
Effects of NaBH4 Additions on Hydrogen Absorption by Nanostructured FeTi Powders
Authors: Marques Sofia F. , Silva Raquel A. , Correia Jose Brito , Shohoji Nobumitsu , Rangel Carmen M.
Published: March 2009

FeTi intermetallic powders are very promising media for reversible hydrogen storage.
However, difficult activation treatments including annealing at elevated temperatures in high
pressure H2 gas atmosphere are mandatory. In the present work nanostructured FeTi powders were
produced and activated in situ at room temperature using mechanical alloying/milling (MA/MM) of
pure metallic constituents, Fe and Ti, added with sodium borohydride. The resultant powders,
FeTiHx, already H2 pre-charged, absorbed a significant amount of H2 but require optimization for
reversible absorption/desorption. This system has one of the highest volumetric storage capacities
and can be produced at low cost. Several parameters of the as-milled powders were controlled. The
phase constitution of the reaction products was characterized by X-ray diffraction and scanning
electron microscopy and the absorption isotherms of the activated powders were determined.
An Impedance Study on the sPEEK/ZrO2 Membranes for Direct Methanol Fuel Cell Applications
Authors: Silva V.B. , Silva V.S. , Madeira L.M. , Pereira Nunes Suzana , Mendes A.
Published: March 2009

Electrochemical impedance experiments were carried out in order to study the influence
of the ZrO2 inorganic incorporation on the proton conductivity of sulfonated poly(ether ether
ketone) (sPEEK) membranes. The impedance data was fitted to an extension of Randles’ circuit,
within the inorganic content and temperature ranges considered. The model fits quite well for ZrO2
loads up to 10 wt.%. Such a model allows for characterizing the diffusion phenomena (Warburg) of
the membrane electrode assembly (MEA), membrane and electrodes resistances, capacitive and
inductive behavior. Proton conductivity was obtained from the impedance spectra and it was
observed that it increases with temperature and decreases with the inorganic content. As a general
trend, the Warburg parameter decreases slightly with the temperature, except for the 5 wt. % ZrO2
membrane that suffers a more pronounced influence. The Warburg parameter also decreases with
the ZrO2 content.
The Effect of the Carbon Epoxy Plate’s Size under Low Velocity Impact
Authors: Amaro Ana M. , Reis Paulo N.B. , de Moura Marcelo F.S.F.
Published: March 2009

The aim of present work is to study the influence of the plate’s size on low velocity
impact on carbon-fibre-reinforced epoxy laminates. Experimental tests were performed on [04,904]s
laminates, using a drop weight-testing machine. Circular, square and rectangular plates were tested
under low velocity impacts using a hemispherical impactor with 20 mm diameter and 3 J impact
energies. The impacted plates were inspected by X-radiography. Numerical simulations were also
performed considering interface finite elements compatible with three-dimensional solid elements,
which allows to model delamination onset and growth between layers. The results showed that the
plate’s size has influence on the delaminated area. Good agreement between experimental and
numerical analysis for shape, orientation and size of the delaminations was obtained.
Mechanical Behaviour of FSW Aluminium Tailored Blanks
Authors: Leal Rui M. , Chaparro Bruno M. , Antunes Jorge M. , Vilaça Pedro , Rodrigues Dulce Maria Esteves , Loureiro Altino
Published: March 2009

The mechanical behaviour of homogeneous and inhomogeneous FSW aluminium tailored
blanks is analysed in this paper. The heterogeneity in mechanical properties across the different
weld zones is discussed based on hardness testing results. Tensile and formability test results are
also shown and the mechanical behaviour of the welds is discussed in relation to the base materials.
Despite the hardness tests have indicated very small differences in hardness, between the welds and
the base materials, and the tensile test results also showed similarities in mechanical behaviour, the
formability tests revealed additional difficulties in forming the welded sheets.
Influence of Wear Properties on Fretting Fatigue Life of a CK45 Alloy and the Al7175 Alloy
Authors: Buciumeanu M. , Miranda A.S. , Silva F.S.
Published: March 2009

The main objective of this work was to study the influence of the wear properties of two
commercial alloys (CK45 and Al7175) on their fretting fatigue behavior. It is verified the effect of
material local degradation by wear on a fatigue strength reduction factor, namely the stress
concentration factor, and on the overall fretting fatigue life of these materials. The fretting fatigue
phenomenon is a synergetic effect between wear and fatigue. It is dependent on both the fatigue and
the wear properties of the materials. Material properties promoting an increase in wear resistance
should enhance fretting fatigue life.
Bitumen Morphology as Observed by Phase-Detection Atomic Force Microscopy
Authors: Costa Elisabete R. , Colaço Rogerio , Diogo António Correia
Published: March 2009

An analysis of the microstructure of several modified bitumen shown by phase detection
Atomic Force Microscopy (AFM) is presented here. The phase detection and topographic AFM
images, displayed three different types of microstructure: the so-called catana phase domains (beelike
structures) dispersed in the peri-phase are present in most of the cases; para-phase domains are
also observed in the neighbourhood of both catana and peri-phases. These results are consistent
with the picture of bitumen as a heterogeneous mixture, as one should expect. The proportions of all
these phases display a rather strong dependence on the nature of the modified bitumen considered,
on the concentration of the modifier, as well as on the amount of aging of the mix.
Static and Fatigue Resistance of GRP Materials and Flywheel Disc of a Storage Unit for Environmentally Friendly Urban Vehicles
Authors: Černý Ivo , Jeronimidis George , Mayer Rayner M. , Medlicott Phil
Published: March 2009

The paper presents results of a partial experimental programme carried out within the
project EUREKA E! 2462 TRUS, which aim is to demonstrate a novel form of hybrid electric drive
line without the need for overhead lines. The zero emissions public transport vehicle is based on a
hybrid electric drive line with novel, strongly innovative features. The concept includes the use of a
small on-board energy storage unit (flywheel) to store the energy that would otherwise be lost on
braking. Results of an experimental complex programme of an evaluation of static mechanical and
fatigue properties of long glass-fibre reinforced polyester composite material with biaxial or
multiaxial structures, respectively, to be used for a manufacture of the flywheel hub disc are
presented in the paper. It was shown that results of interlaminar shear fatigue strength of the disc
mostly almost correspond to those obtained on basic material – biaxial GRP plates and are close to
results obtained on a similar uniaxial GRP used for railways springs. Some ascertained differences
are discussed.
Surface Singularity Upon Solar Radiation Heating of Graphite/Tungsten Powder Mixture Compacts to Temperatures in Excess of 1600°C
Authors: Oliveira Fernando A. Costa , Granier Bernard , Badie J.M. , Fernandes Jorge Cruz , Rosa Luis Guerra , Shohoji Nobumitsu
Published: March 2009

Synthesis of single-phase tungsten sub-carbide W2C was attempted by heating pellets
made out of a source of carbon (graphite-G) and W powders with G/W atom ratio between 0.35 and
0.50 to two target temperatures, namely 1600°C and 1900°C in an argon atmosphere using a solar
furnace at PROMES-CNRS in Odeillo (France). The results showed that synthesis of single-phase
W2C phase was difficult at either target temperature yielding the W2C co-existed with free metallic
W. It was noted that the thin top surface layer of the solar-synthesised tungsten carbide pellets
heated to 1900°C was distinguishable from the rest of the bulk specimen showing localised growth
of nano-meter scale WC whiskers over W2C grains. Detailed XRD (X-ray diffraction) results on the
effect of both G/W ratio and temperature on W2C lattice parameters are discussed.
Properties of Carbon Nanotube - Polymer Composites
Authors: Major Andrea Ádámné , Belina Károly
Published: March 2009

In the last ten years carbon nanotube composites are in the focus of the researchers of
polymer blends. Different composition of carbon nanotubes and polymers were produced by a
special mixing unit called Infinitely Variable Dynamic Shear Mixer (IDMX). In the experiments
polypropylene and polycarbonate polymers were used as matrix materials. Nanotube masterbatches
were used to prepare different compositions. Concentration series were manufactured by the
dynamic mixer. The prepared materials were characterised by scanning electron microscopy.
Mechanical, electrical and burning properties of the materials were also determined. Thermal
properties were examined by DSC.
The Comparison of Solid Silicone Rubber Types Manufactured by Diverse Technologies
Authors: Muka István , Huba Antal
Published: March 2009

The paper presents the current results of our ongoing research on the field of silicon
rubber applications in precision engineering and in medical industry. We have demonstrated two
technologies for the manufacturing of precision parts and devices for the medical industry. The
mechanical properties of the silicone rubber materials manufactured by press vulcanisation and by
moulding (diving) are compared.
Decomposition of the Ferritic Phase in Isothermally Aged SAF 2507 Duplex Stainless Steel
Authors: Berecz Tibor , Mészáros István , Szabó Péter János
Published: March 2009

Duplex stainless steels constitute a famous group of the stainless steels. They consist of
mainly ferritic and austenitic phases. The ratio between these phases is regulated by numerous
alloying elements and low content of carbon. Because of this strong alloying a lot of metallurgical
processes can take place at high temperature, e.g. the decomposition of ferritic phase into σ-phase
and secondary austenite. In this paper the changes of amounts of these three phases are studied by
automated EBSD, saturation magnetization measurement, XRD-analysis and micro-hardness test.
Similar results were obtained by the different applied measurements for the change of phase ratios
due to the isothermal heat treatment.
Decomposition of Magnetic Phases in Alloys
Authors: Mészáros István
Published: March 2009

In this paper we present a study of the separation of phases in multi-phase alloys. The
proposed technique is based on the hyperbolic model of magnetization. In this work the normal
magnetization curve of the model was fitted to the measured one. It is possible to decompose the
magnetic phases of alloys and determine their magnetic properties separately by using the
determined model parameters. Experimental verification was carried out on a transformer like setup,
constructed from layered samples. The samples were constructed from elements of strongly
different magnetic properties. The results given by the model are in an excellent agreement with the
experimental results, giving justification for the proposed method of decomposition. The proposed
method could become a vital tool in magnetic investigations.
Investigation of Basalt Fiber Reinforced Polyamide Composites
Authors: Deák Tamás , Czigány Tibor
Published: March 2009

Basalt fiber reinforced polyamide composites were investigated to determine their static
and dynamic mechanical properties. The composites were compounded in an extruder and were
injection molded. A glass fiber reinforced composite also was investigated. Two different basalt
fibers were used with silane sizing and one of them was used also without sizing. The results show
that composites with silane sized basalt fibers have properties similar to glass fiber reinforced
composites, while unsized basalt fibers eventuate smaller strength and higher brittleness.
Dislocation Networks Formed by Silicon Wafer Direct Bonding
Authors: Reiche Manfred
Published: March 2009

The paper reviews methods of hydrophobic wafer bonding. Hydrophobic surfaces are
obtained by removing the oxide layer from the surfaces of crystalline silicon substrates. Bonding
such surfaces causes the formation of a dislocation network in the interface. The structure of the
dislocation network depends only on the misalignment (twist and tilt components). The different
dislocation structures are discussed.
Because wafer bonding offers a method to the reproducible formation of such networks, different
applications are possible
Processing Aluminum Scrap Vial Mechanical Alloying and Subsequently Hot Extrusion
Authors: Coelho Rodrigo Estevam , Esteves Paulo Jesus Costa , Ferreira Brito Jorge
Published: March 2009

Recycle aluminum cans, an alternative route is presented in this work. The aluminum
cans are cut in little flakes with a shears, and then the materials were milled, obtained fine powders.
The weight ratio of the balls to powder was 10 to 1. Equipment of a horizontal high energy ball mill
was utilized. The powder mixture was processed during 0.5, 1 and 2 hours at 950 rpm and after
milling, the powders were directly hot extrusion. The extruder bars were submitted at a tensile tests
and samples microstructures were analyzed by optical microscope. Experimental results obtained
shows that the technique utilized in this work is very important for economized routes and
consequently, less expensive, as compared with conventional methods.
Processing and Mechanical Properties of PM Processed Fe-Cu-Co Alloys
Authors: Barbosa A.P. , Oliveira L.J. , Bobrovinitchii Guerold Sergueevitch , Guimarães R.S. , Crespo S. , Filgueira Marcello
Published: March 2009

In this work, a study to process and characterize Fe-Cu alloys with reduced Co content is
shown. The Fe-Cu-Co alloys were processed by elemental blending of powders of the system Fe-
15%wtCu with various amounts of Co, pressing at 350MPa, and sintering at 1150°C/25min./10-2
mbar. The sintered microstructure was observed. It was conducted hardness and wear tests, aiming
to define the ideal Cu addition for future use in impregnated diamond tools. It was observed that
higher Co contents results in improved hardness and wear resistance in the studied Fe-Cu alloys.
Identification of the Spouted Bed Flow Regime by Simulation and Experimental Data
Authors: Lourenço R.O. , dos Santos Kássia Graciele , Murata Valéria V. , Duarte Claudio Roberto , Henrique Humberto Molinar , Barrozo Marcos A.S.
Published: March 2009

The particle circulation rate and gas–solid contacting efficiency are important parameters
for the project of spouted beds, applied in many industrial processes. Due to the restrictions found
in the identification of flow regimes through visual observation, new techniques have been
developed to obtain a better gas and particle dynamics description, necessary for the evaluation of
these parameters. One of these techniques has been the CFD simulation. In this work the pattern of
solids and gas flows in a spouted bed was numerically simulated using a 3D Eulerian multiphase
model. Soybean particles had been used in the attainment of data of pressure drop fluctuation and
power spectrum as a function of gas velocity in an experimental apparatus. The 3D simulated solids
volume fraction profiles allow the identification of the flow regimes showing a good agreement
with the experimental data.
Synthesis Methods Evaluation for Preparation of the Zno:Co Diluted Magnetic Semiconductor (DMS)
Authors: Gama Lucianna , Ribeiro M.A. , Vieira Débora A. , Santos A.M.C. , Kiminami Ruth Herta Goldsmith Aliaga , Weber I.T. , de Melo Costa Ana Cristina Figueiredo
Published: March 2009

Diluted magnetic semiconductors (DMS), which have both semiconducting and magnetic
properties, are those in which transitions metal ions substitute cations of host semiconductor
materials [1]. There is a great interest for DMS for use as the material of spintronics. In this study is
reported the structural and morphologic characterization of Zn1.95Co0.05O nanoparticles obtained by
Pechini method and combustion reaction. The powders resulting were characterized by X-ray
diffraction (XRD) for determination of the phases, crystalline phase and lattice parameter; nitrogen
adsorption by BET for determination of the specific superficial area and calculation the particle size
from the superficial area and scanning electron microscopy (SEM) for morphologic analysis. The
XRD results demonstrated the viability of obtaining crystalline and nanosize powders by the both
synthesis routes. For all samples the average crystallite sizes was nanosized, but the powders
obtained by reaction combustion is smaller. The SEM micrographs shows that the powders obtained
for both syntheses are constituted of soft agglomerates.
Effect of a LZSA Glass Infiltration on the Properties of a Porous Ceramic Composite Material Derived from Polysiloxane/Al/Nb
Authors: Acchar Wilson , Diniz Marcus , Fonseca Ygor Alexandre A. , Costa F.C.C.
Published: March 2009

By using the active filler controlled polymer pyrolysis, new and cost-effective composite
materials can be obtained. In this work, ceramic matrix composites were prepared by using this
precursor route, using a polysiloxane network filled with metallic niobium and aluminum powders
as active fillers. The mixtures were blended, uniaxially warm pressed, and pyrolyzed in flowing
argon at 1400 °C. Porous ceramic preforms were infiltrated with a LZSA glass material, in order to
improve the density of a porous composite material. The properties of the pyrolyzed composite
material and the effect of the LZSA infiltration on the Al2O3-NbC-SiOC ceramic composite
material were investigated. The results have showed that the infiltration processes has improved the
physical and mechanical properties of the composite material.
Use of Ornamental Rock Waste in Porcelain Tile
Authors: Souza A.J. , Pinheiro Bruno C.A. , Sousa S.J.G. , Holanda J.N.F.
Published: March 2009

The ornamental rock industry generates huge amounts of waste in form of fine powder,
demanding adequate alternatives for its final disposal. The possibility of using ornamental rock
waste as a flux in porcelain tile has been assessed. The porcelain tile formulations are constituted
mainly by kaolin, feldspar and quartz. The waste was added to a typical porcelain tile body,
replacing the sodic feldspar by up to 15 wt. %. The prepared pastes were fired of 1240°C using a
fast-firing cycle. The specifications of porcelain floor tile in terms of physical properties were
achieved.
Deposition of Strontium-Doped Lanthanum Manganite Suspensions by Wet Powder Spraying
Authors: Chiba Rubens , Vargas Reinaldo Azevedo , Andreoli Marco , Seo Emília Satoshi Miyamaru
Published: March 2009

The compound strontium-doped manganite lanthanum (La0,85Sr0,15MnO3 - LSM),
deposited in the form of thin films in yttria-stabilized zirconia substrate (Y2O3/ZrO2 - YSZ), is of
basic importance as cathodic material of the solid oxide fuel cells (SOFC). In this work, the LSM
was synthesized by the citrate technique and characterized by X-ray fluorescence spectroscopy
(XRF), phase analysis light scattering granulometry (PALS), X-ray diffractometry (XRD) and
scanning electron microscopy (SEM). In the wet powder spraying, was used an airbrush and the
LSM sample deposited to the YSZ substrate was sintered and characterized by SEM. The
conclusions had allowed to establish preliminary conditions for preparation of LSM suspensions by
wet powder spraying.
Characterization of Granulometric Fractions of Ash from Boiler Burnt Sugarcane Bagasse
Authors: Gadioli Monica Castoldi Borlini , Vieira Carlos Maurício Fontes , Rodríguez Rubén Jesus Sánchez , Conte R.A. , Pinatti Daltro Garcia , Monteiro Sérgio Neves
Published: March 2009

In the municipal area of Campos dos Goytacazes–RJ several ceramic industries are
involved with a significant production of bricks and tiles. These ceramic products can serve as
matrices for the incorporation of industrial residues such as the ash of sugarcane bagasse used as
fuel in the boilers of the sugar and alcohol plants. The incorporation of ashes in ceramics is a
solution that eventually can cause an improvement on the properties of the material. The objective
of this work is to characterize granulometric fractions of sugarcane bagasse ash with particle sizes
less than 149, 75 and 44 μm aiming at the ash incorporation into red ceramics. Chemical,
mineralogical and microstructural characterization were carried out in the granulometric fractions.
The results showed that the granulometric fractions present as main crystalline phase the cristobalite
and that the ashes with smaller particle sizes can improve the densification of the ceramic body by
the formation of more liquid phase during firing, due to the presence of less silica and more
alkaline- and alkaline-earth oxides than the original ash.
Characterization of Clay from Vale do Mulembá - ES
Authors: Gadioli Monica Castoldi Borlini , Correia J.C.G. , Caranassios A.
Published: March 2009

This work has for objective to characterize the clay from Vale do Mulembá-ES. The Vale
do Mulembá is located in Joana D´Arc, Vitória in Espírito Santo State, Brazil. That clay is used in
the production of the traditional clay pans of the State, what contributes to the economy of the area.
The clay from Vale do Mulembá presents characteristics and behavior different from the other clays
used for the production of clay pans. The characterization studies were carried out through chemical
analysis, X-ray diffraction, particle size distribution, plasticity and thermal analyses (DTA, TGA).
The results showed that the clay is typical kaolinitic, present relatively to the amount high of Al2O3
and high plasticity.
Thermal Treatment of the AISI M2 High Speed Steel Promoted by a CO2 Laser Beam
Authors: de Vasconcelos G. , dos Reis J.L. , Campanha M.V. , da Silva A.F.
Published: March 2009

The purpose of this paper is the evaluation of the use of a low power CO2 laser beam
(50W) to promote the thermal treatment of AISI M2 high-speed steels and evaluate the tribological
properties of the graphite coating that takes place on the steel surface after laser irradiation. In order
to minimize the steel surface reflection at approximately 90% of the incident radiation wavelength
(10.5 μm), an incident radiation absorber layer was applied to the steel surface sample. This coating
aims to absorber the incident heat and transfer part of heat to the steel surface. As results the surface
presented high hardness and a thin coating of graphite on the surface. The micro-structural changes,
occurred on the steels surface, resulting from heat transfer from the absorbing layer, were evaluated
through optical microscopy (MO), scanning electron microscopy (MEV), micro-hardness essays
(MH), X-ray analysis (XRD), Raman spectroscopy and tribological testers on the graphite coating.
MO analysis showed on the transversal section of the heated affected zone a brighter layer than the
sample’s core, 30 micrometers thickness, in the surface sample a black coat 10 micrometers
thickness. By MH analysis this brighter layer presented hardness approximately 30% superior than
the regions without treatment, and by Raman spectroscopy it was evaluated the graphite coating.
The XRD analysis on the surface sample reveals an increasing of the martensite and iron-carbide
phase. The experimental results of pin-on-disk tests on the graphite coatings reveal a reduced
coefficient friction as compared to the original surface.
Creep of Si3N4 Based Ceramics for Thermo-Mechanical Applications
Authors: dos Santos Claudinei , Strecker Kurt , Barboza M.J.R. , Neto Francisco Piorino , Silva Olivério Moreira Macedo , Silva Cosme Roberto Moreira
Published: March 2009

Commercial α−Si3N4, Al2O3 and a mixed yttrium and rare earth oxides, RE2O3, were
used as starting-powders. Powder batches were milled using different Al2O3/RE2O3 contents, as
additive. Hot-pressing was done at 1750oC-30 min-20MPa in N2 atmosphere. Specimens neat to
6x3x3mm3 were polished and characterized by XRD and SEM. Specimens were submitted to creep
tests, under compressive stresses between 100 and 350 MPa at temperatures ranging from 1250 to
1300oC in air. Higher additive amounts resulted in larger grains of higher aspect ratios and in a
decreased anisotropy in the hot-pressed ceramics. The compressive creep behavior depends on the
intergranular phase content. While higher amounts of additives resulted in higher creep rates,
•
ε , and
higher stress exponents, n, the activation energy Qss, has been inferior for samples with lower
additive contents. Grain sliding has been identified to be the predominant mechanism responsible
for creep deformation of these ceramics.
Evaluation of Biomimetic Solution for Coating Powder Metallurgy Porous Titanium Samples
Authors: Silva de Medeiros Waléria , de Oliveira Marize Varella , Granjeiro José Mauro
Published: March 2009

In order to improve implant-bone attachment, porous titanium has been used to achieve
the ingrowth of bone tissue within the porous structure. Although this biomaterial has shown
efficient bone adhesion for orthopedic and dental implants, the ideal surface must have chemical
bonds at the implant-bone interface. In this work, samples of pure porous titanium were produced
by powder metallurgy technique and submitted to biomimetic process in order to evaluate the
material’s bioactivity and to enhance its osteoconductivity. The samples were immersed in modified
simulated body fluid (mSBF) which induces the nucleation and growth of a calcium phosphate
bioactive film and a chemical bond with titanium. SEM, EDX and FTIR analyses showed that a
calcium phosphate deposition occurred without the need of pre-treatments to increase the surface
bioactivity. As a result, this research revealed the potential for obtaining a bonelike apatite film on
this porous titanium by biomimetic method.
Influence of Synthesis Route on Phase Formation and Sinterability of Hydroxyapatite-Zirconia Composites
Authors: Lazar Dolores Ribeiro Ricci , Cunha Sandra Maria , Ussui Valter , Fancio E. , de Lima Nelson Batista , Bressiani Ana Helena A.
Published: March 2009

Reinforcement with yttria stabilized zirconia (YSZ) is an alternative to improve
mechanical strength of hydroxyapatite (HAp) ceramic. However, calcium may react with zirconium
to form calcium zirconate. In addition, decomposition of HAp to tricalcium phosphate (TCP) occurs
with water loss inhibiting ceramic densification. In order to minimize the formation of these
compounds, two synthesis routes were compared in this work: coprecipitation of hydrous yttria
stabilized zirconia in a calcium phosphate gel medium and powder mixture of individual calcined
powders. Composite nominal compositions were fixed at 90 and 95 HAp wt%. Calcium, zirconium
and yttrium chlorides and ammonium hydrogen phosphate were the employed precursors.
Ammonium hydroxide was the selected precipitation agent. Calcination was performed at 800oC for
1 hour and pellets were sintered in the range of 1150 and 1350oC for 1, 3 and 5 hours. Ceramic
samples were characterized by scanning electron microscopy and apparent density measurements.
Crystalline phases were quantified by Rietveld analysis of X-ray diffraction patterns. Results
indicate that powders prepared by coprecipitation can cause porosity formation due to the higher
chemical reactivity during synthesis process.
Comparison of Structure and Properties of the PVD, Hybrid (Galvanic + PVD), and Galvanic Coatings Deposited onto the Brass Substrate
Authors: Dobrzański Leszek Adam , Lukaszkowicz Krzysztof
Published: March 2009

The properties of thin hard coatings and consequently their functionality are influenced
by microstructural characteristics such as mechanical properties. A variety of interlayers has been
used in hybrid coatings for various purposes. The paper presents investigation results of the
structure, erosion and corrosion resistance, and mechanical properties of the galvanic Ni/Cr, hybrid
Ni/Cr + Zr/ZrN (galvanic + PVD) and monolithic nitride coatings deposited by PVD technique (dc
magnetron sputtering) onto brass (CuZn40Pb2) substrates. The ceramic PVD coatings or layers are
the Cr-, Ti-, TiAl-, Zr-nitrides. The investigation covered the metallographic analysis on the
scanning electron microscope, mechanical properties and erosion test. The corrosion tests were
made in a 1 M NaOH solution. It was found out that PVD coatings display high corrosion
resistance.
Microstructure and Magnetic Properties of PrFeCoBNb Sintered Magnets Produced from HD and HDDR Powders
Authors: Ferreira Eliner Affonso , Silva S.C. , Périgo E.A. , de Faria Jr. Rubens Nunes , Takiishi Hidetoshi
Published: March 2009

Sintered magnets have been produced with powder obtained using the hydrogenation,
disproportionation, desorption and recombination process (HDDR). The new processing procedure
for the production of the sintered magnets has been adopted in an attempt to reduce the milling
time. Commercial cast ingot alloys based on the compositions Pr14Fe75.9Co4B6Nb0.1 and
Pr20.5FebalB5Cu2.0 have been employed in this investigation. The HDDR powder was used to
produce sintered magnets using a mixture of these alloys, in very distinct proportions. Only a small
amount (20 wt. %) of the copper-containing alloy has been added as a sintering aid. Standard
hydrogen decrepitation (HD) magnets have also been included in this work for a comparison. The
effect of a reduced milling time on the magnetic properties of the HDDR sintered magnets has been
investigated. Sintering temperature and time of were kept constant for all magnets (1050°C for 60
minutes). The microstructures of the permanent magnets have been investigated by scanning
electron microscopy and energy dispersive X-ray analysis.
Effects of Al2O3 Particles Addition on Compressibility and Sinterability of Aluminium Powder Allows
Authors: Oliveira J.L.A. , Fogagnolo J.B.
Published: March 2009

There is considerable industrial potential for aluminium alloys and aluminium metal matrix composites fabricated via net shape press-and-sintering powder metallurgy using low-cost, elemental premixed powder. In this work, the compressibility and sinterability of premixed Al– 4.5Cu–0.7Si–0.5Mg powder alloy reinforced with Al2O3 particles was analyzed. The powders reinforced with increasing ceramic particle content were cold-pressed under increasing pressure and sintered at 600 oC for 40 minutes, in nitrogen atmosphere. The powders showed the typical compressibility curves and the presence of hard ceramic particles decreased the powder deformation capacity and, consequently, the powder compressibility. The sintering produced swelling of the parts, due to the poor wettability of liquid phase on the aluminium particles and to the Kirkendall effect caused by the difference in diffusivity of aluminium in copper and copper in aluminium. The presence of Al2O3 particles increased the swelling during sintering probably due to the sooner formation of liquid phase.
The Effect of Niobium and Boron Content on Magnetic Properties and Corrosion Resistance of Pr-Fe-Co-B-Nb HD Magnets
Authors: Angelo J.D. , Motta C.C. , Barbosa Luzinete Pereira , Takiishi Hidetoshi , Costa Isolda , de Faria Jr. Rubens Nunes
Published: March 2009

The hydrogenation decrepitation process was employed to produce sintered magnets using a mixture of two alloys. The effect of niobium and boron content on the magnetic properties of Pr14FebalCo16BxNby-type sintered magnets was studied. Niobium and boron have a significant effect on the magnetic behavior of these permanent magnets. The optimum amount of boron was 6 at% and niobium should be kept below to 0.50 at%. The squareness factor (0.90) has been improved considerably and good overall magnetic properties (Br=1320 mT, iHc=700 kAm-1 and (BH)max=315 kJm-3) have been achieved for the sintered magnets prepared from the Pr14Fe63.85Co16B6Nb0.15 alloy.
Automation Finish Processes of Sword Surface Using Burnishing Assistance
Authors: Pa Pai Shan
Published: March 2009

A new method of automated finishing that employs a nonconductive stone as the
burnishing tool to execute burnishing assistance in electrochemical finishing following sword
machining is investigated. The submitted processes can be used for various sword-form operations.
Among the factors primarily discussed is the performance of electrochemical finishing combined
with burnishing. In the experiment, an electrode is used with continuous and pulsed direct current.
The controlled factors include the material of burnishing tool, the geometry of burnishing tool, and
the chemical composition and concentration of the electrolyte. The experimental parameters are
flow rate of electrolytes, feed rate of electrode and burnishing tool, electrical current rating, and
pulsed period. Higher current rating with a quicker feed rate of the finishing tool effectively reaches
the fast improvement of the surface roughness of the workpiece. The use of a large electrolytic flow
rate is advantageous to the finish effect. The finish effect is better with longer off-time because
discharge of the finish dregs becomes easier. The use of pulsed current, however, raises the
machining time and cost. The design change of the electrochemical finishing to the electrochemical
finishing and burnishing performs the best finishing make the surface of the swords smooth and
bright. An effective and low-cost automation and the continuity finish processes through the design
tool and using the burnishing assistance in the electrochemical finishing are high efficiency and
low-cost means.
Design and Fabrication of a General Purpose 3D Digitizer Based on Grinding Technique
Authors: Lee Wei Chen , Chen Liang Wei
Published: March 2009

The objective of this research is to design and fabricate a general purpose 3D digitizer based on
grinding technique to completely acquire the geometry of an object, including its inner structure, and
accurately create its CAD model. How the 3D digitizer works is as follows. First a thin layer of an
object that is fixed in epoxy is removed by a grinder and the image of the cross section is taken by a
CCD camera. The process is repeated until the images of all the cross sections of the object are
captured. Then the images are stacked up by using software 3D-DOCTOR to obtain the 3D CAD
model.
The accuracy of the 3D digitizer developed in the research was within 0.03 mm when measuring a
length of 5.50 mm and the gauge R&R percentage was 25.99%. The performance shows that the 3D
digitizer is promising for use in industry.