bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrical Resistivity, Thermopower and Magnetic Susceptibility of Nonstoichiometric BaVS3
Authors: Ohtani Tsukio , Obana A. , Harada K.
Published: March 2009

Quasi-one-dimensional sulfide BaVS3 is known to show a metal-to-semiconductor transition at ~70
K. In this study we investigated the effects of nonstoichiometry of BaVS3 on this transition.
Single phase samples were obtained in the composition ranges of 0.95 ≤ 1±x ≤ 1.05 in BaV1±xS3,
and of 0.95 ≤ 1-x ≤ 1.00 in Ba1-xVS3. All single phase samples showed the
metal-to-semiconductor transition at ~70 K. Seebeck measurements revealed that the dominant
carriers are electrons in all samples. BaV1.05S3 and Ba0.98VS3 showed relatively large values of the
power factor of about 1.0 x 10-4W/K2m around 200 K.
Selective Transmission of Electromagnetic Wave by Using Diamond Photonic Crystals with Graded Lattice Spacing
Authors: Kirihara Soshu , Miyamoto Yoshinari
Published: March 2009

Three-dimensional electromagnetic or photonic crystals with periodic variations of the
dielectric constants were fabricated by using a rapid prototyping method called stereolithography.
Millimeter-order epoxy lattices with a diamond structure were designed to reflect electromagnetic
waves by forming an electromagnetic band gap in GHz range. Titania based ceramic particles were
dispersed into the lattice to control the dielectric constant. The diamond lattice structures formed the
perfect band gap reflecting electromagnetic waves for all directions. The location of the band gap
agreed with the band calculation using the plane wave propagation method. The diamond structures
with graded lattice spacing were successfully fabricated as well, resulting in the directional
transmission of microwaves. The stretching ratio of the lattice spacing in the crystal structure was
changed according to the electromagnetic band calculation. A microwave antenna head composed of
the diamond structure with graded lattice spacing was fabricated which achieved the unidirectional
transmission.
Grain-Focused Microstructure Simulations: Stress-Induced Evolution of Polycrystalline Films
Authors: Bentz Daniel N. , Bloomfield Max O. , Cale Timothy S.
Published: March 2009

We discuss simulations of grain boundary motion utilizing a grain-continuum approach to
representing polycrystalline films; i.e., as a system of distinct but interacting continua. Field
variables are computed as functions of position in each grain; e.g., internal stresses and
concentrations. Grain boundaries are represented and tracked using multiple level sets, providing a
method to evolve the grain structure in time. We demonstrate the approach using stress-driven grain
boundary migration in polycrystalline copper films, assuming that migration is due to vacancy
migration. The anisotropic elastic constants of single crystal copper are used for each grain, under
specified rotations (grain orientations). Stresses and stress gradients are thermally induced in a film
with <111> texture, with the exception of a single <100> grain on a silicon dioxide film on a silicon
substrate. Grain boundary velocities are calculated from the fluxes of vacancies to grain boundaries.
The computed velocities are then used to update the level sets that represent the grain boundaries.
Ceramic and Cermet Coatings for Cylinder Liner in Ultra Light Weight Engines - Novel Processing and Manufacturing of Ceramic Layer Composites
Authors: Gadow Rainer , López D. , Candel A.
Published: March 2009

Actual requirements in the automotive industry are the reduction of fuel consumption
and pollution emission, engine efficiency improvement, as well as cost reduction. Most of these
requirements are fulfilled by reducing the total weight of the vehicle. This results in an increasing
utilization of light metal components for engine applications. Significant weight savings are
obtained by changing the engine block material from cast iron to aluminum or even to magnesium
aluminum hybrid constructions.
Despite of all advantages the industrial implementation of light metals is often inhibited by their
poor surface properties especially concerning wear and tribological behavior. Due to the highly
loaded operation conditions a cylinder liner surface reinforcement is necessary.
A very promising technological alternative is the internal cylinder reinforcement by using HVOF
(high velocity oxygen fuel) sprayed coatings. By using these advanced high energetic coating
technologies, material combinations containing solid lubricant ceramic dispersions can be
deposited. The thermal spray processes represent a cost effective and flexible solution for ultra light
weight engine technology. This research is focused on the development of HVOF sprayed coating
systems for cylinder liners, the coating optimization and the cost effective implementation of this
hypersonic spray technology in a series production process.
It will be shown that cast engine block bores can be directly coated by using an automated
HVOF process, obtaining improved coating results. The internal coating process by hypersonic
flame spraying is a superior technological alternative to the APS process for high quality cylinder
liner and engine crankcase applications.
Preparation of Cu/GDC Cermet Anode by Sintering via Surface Modification with MgO Sol
Authors: Han Kyoung Ran , Jeong Youn Ji , Kim Chang Sam , Lee Hai Won
Published: March 2009

CuO/GDC composite powder with 50 wt% of CuO was prepared by surface modification
of ~60 nm GDC powder with Cu precursors. Since copper oxide melts at lower temperature than
GDC sintering temperature, fabrication procedure was modified by inducing infiltration of molten
copper oxide via capillary force and then followed by heat treatment at ~1000 °C . Surface
modification was carried out with a MgO sol to suppress agglomeration of GDC. Such prepared
Cu/GDC cermets showed uniform microstructure and excellent electric conductivity of ~6000 S/cm
for the Cu/GDC cermet and ~10000 S/cm for the modified one at 800°C.
Spark Plasma Synthesis/Sintering of Dense Ceramic, Intermetallic and Composite Materials
Authors: Locci Antonio Mario , Licheri Roberta , Orrù Roberto , Cincotti A. , Cao Giacomo
Published: March 2009

Spark Plasma Sintering (SPS) represents a very attractive technique for the obtainment of
dense materials including nanostructured ones. SPS basically consists in the simultaneous
application of a pulsed DC current and an uniaxial mechanical load through a powder compact.
Other than providing rapid Joule heating and likely enhancing mass transport through
electromigration, the imposed pulsed high current is also reported to generate a plasma within the
voids surrounding the powder particles, thus facilitating the removal of oxides surface layers that
may hinder the sintering process. Selected results obtained through SPS in our laboratory for the
preparation of a wide variety of materials, i.e. TiC-TiB2, MgB2, and NbAl3, will be presented in this
work. Specifically, all the chosen examples are related to the use of the SPS technique for obtaining
the desired material by simultaneously performing synthesis and consolidation stages in one-step.
Corrosion of Si3N4-Ceramics in Acids and Basics
Authors: Schilm Jochen , Herrmann Mathias , Michael G.
Published: March 2009

The corrosion behavior of silicon nitride materials in aqueous media strongly depends on
the composition and amount of the grain boundary. But there exist no systematic investigations of
the relation between the corrosion behavior and the composition and amount of the grain-boundary
phase. The subject of this study is based on the evaluation of the corrosion mechanisms of Si3N4
ceramics and YSiAlON glasses, both with defined and characterized compositions, in acidic and
basic environments with different concentrations. Special effort has been made in describing the
compositions of grain boundary phases in the sintered Si3N4 ceramics. A model to describe
structural features of YSiAlON-glasses was developed which allows the correlation of the corrosion
behavior of the ceramics and the glasses with their compositions. In combination with SEM and
TEM investigations it became possible to give structural reasons for the different observed
corrosion mechanisms.
Influence of Oxygen and Titanium Modification of AlN Surface on the Properties of Direct Bonded AlN-Cu Joints
Authors: Olesinska W. , Kalinski D. , Chmielewski M.
Published: March 2009

The paper presents the results concerning the formation of a ‘barrier’ layer on AlN
ceramic during its joining with copper by the Copper Direct Bonding (CDB) technique. Prior to the
joining, the AlN surface was modified by isothermal oxidation or by titanium ion implantation. The
effects of the oxidation process temperature were examined within the temperature range from 673
to 1473K. The surface of the ceramic was modified by titanium ion implantation at various ion
doses and various accelerating voltages. The modified ceramic was joined with oxidized copper in a
nitrogen atmosphere with about 1.5ppm of oxygen, using a belt-type furnace at a temperature of
1323K. The microstructure and phase changes induced on the surfaces of the joints were examined.
The modification yielded a ‘barrier’ layer (TiN), which ensured a continuous pore-less contact
between the materials being joined. The results obtained under all the experimental conditions
indicate that the implantation gives better effects than thermal oxidation. Ion implantation seems to
be ideally suited for these purposes. The preferential dose appears to be 5*E16ions/cm2 and the
preferential accelerating voltage – 15kV.
Modelling of the Current-Time Characteristics in Anodic Bonding
Authors: Knowles K.M.
Published: March 2009

The state of knowledge of anodic bonding is reviewed, paying particular attention to the
creation of intimate contact and to the microstructure of anodic bonds formed between silicon and
Pyrex. Equivalent electrical circuit models of differing degrees of sophistication which have been
proposed in the literature to predict the current-time characteristics observed experimentally for a
range of conditions of applied voltage and temperature in anodic bonding are critically analysed. It
is shown that relatively simple equivalent circuit models comprising capacitors and resistors can be
used to account for the main features of the observed current-time characteristics, but that these
require the assumption of large relative permittivities for the capacitative components in the models.
Soldering and Brazing Metals to Ceramics at Room Temperature Using a Novel Nanotechnology
Authors: Duckham A. , Levin J. , Weihs T.P.
Published: March 2009

This paper reviews a new, low-temperature process for soldering and brazing ceramics to
metals that is based on the use of reactive multilayer foils as a local heat source. The reactive foils
range in thickness from 40μm to 100μm and contain many nanoscale layers that alternate between
materials with large heats of mixing, such as Al and Ni. By inserting a free-standing foil between
two solder (or braze) layers and two components, heat generated by the reaction of the foil melts the
solder (or braze) and consequently bonds the components. The use of reactive foils eliminates the
need for a furnace, and dramatically reduces the heating of the components being bonded. Thus
ceramics and metals can be joined over large areas without the damaging thermal stresses that are
typically encountered when cooling in furnace soldering or brazing operations. This paper draws on
earlier work to review the bonding process and its application to a variety of ceramic-metal systems.
Predictions of thermal profiles during bonding and the resulting residual stresses are described and
compared with results for conventional soldering or brazing processes. The microstructure,
uniformity, and physical properties of the reactive foil bonds are reviewed as well, using several
different ceramic-metal systems as examples.
Transient Liquid Phase Bonding of Ceramics and Metal Matrix Composites
Authors: Brochu Mathieu , Edelmann Fabian , Valin Robin , Drew Robin A.L.
Published: March 2009

Transient Liquid Phase Bonding (TLPB) is a joining process that uses liquid as medium
for the establishment of an interface between two faying surfaces. In TLPB, as opposed to brazing
process, the careful selection of the interlayer materials and the use of a prolonged heat treatment,
allows for isothermal solidification and results in interfaces possessing potential service
temperature higher than the joining temperature itself. Such a process is attractive for joining
ceramics to metals and composites. In this presentation, the applicability of TLPB for various
systems: Si3N4/FA-129 iron aluminide alloy, Al2O3/Al2O3, Al-Al2O3/Al-Al2O3, Al-Al2O3/Al-SiC
and Al-Al2O3/Al. Results on the interface formation, interfacial microstructure and mechanical
properties will be presented. A comparison of the TLPB joint properties with traditional joining for
similar systems will be illustrated.
Properties Dependency of Alumina - Steel Joints on Bonding Technique
Authors: Chmielewski M. , Kalinski D. , Pietrzak K
Published: March 2009

The development of technologies for joining ceramics and metals is connected with an
introduction of new ceramic materials and new applications of ceramic-metal joints, to work in ever
more difficult conditions. It concerns mainly ceramic-metal joints working at high and variable
temperatures (a facing layer of burners, turbine vanes, etc.) or in a chemically aggressive
environment (chemical apparatuses, purification plants). This paper presents the analysis of the
influence of the bonding technique on thermal residual stresses generated in ceramic-metal joints
and their properties. Technological bonding tests were made using well-known diffusion bonding
and powder metallization techniques, and with elaborated sintered Al2O3-Cr gradient interlayer.
Numerical calculations (the finite elements method) of the state of thermal residual stresses, as well
as the verifying technological tests, were made for the following pair of materials: Al2O3 ceramics -
heat resisting steel. There were also made tests of resistance for sudden temperature changes and for
oxidation at high temperature. There was found a significant effect of the bonding techniques on the
thermal residual stresses and properties of obtained alumina-steel joints.
The Comparative Analysis of the Non-Symmetric Thermal Shock Crack Propagation in Al2O3 and ZrO2 Bars
Authors: Sadowski Tomasz , Librant Zdzislaw , Boniecki Marek
Published: March 2009

The aim of the paper is theoretical modelling and experimental verification of the nonsymmetric
thermal shock crack propagation in compound ceramic Al2O3 and ZrO2. The theoretical
problem formulation concerns the thermal shock problem in a strip or bar made of nonhomogeneous
material, which can exhibit local fluctuation of its mechanical and thermal properties.
Such approach allows for: analysis of the real non-homogeneous ceramic materials and solution of
the composition optimisation problem for composite material with respect to thermal shock
sensitivity. In particular the presented approach enables estimation of the stress intensity factors
during thermal shock for any continuous composition of the ceramic material.
Polarization Light Optical Texture Analysis for the Structural Characterization of CIM Components
Authors: Rauch Johannes , Kern Frank , Gadow Rainer
Published: March 2009

The mechanical properties of ceramic injection molded (CIM) components are largely
influenced by microstructural inhomogeneities that result from the interaction of rheological
properties of the thermoplastic feedstock with machine parameters and the design of mold and
injection gate. These inhomogeneities (e. g. texture, turbulences, joints, and density gradients) can
form weak spots in the material or lead to anisotropy of the material properties. Additionally, they
can influence the local sinter shrinkage behavior and thereby lead to the formation of residual
stresses in the component. For this reason, it is of great importance to analyze these
inhomogeneities in order to improve CIM processes and CIM components.
A method has been developed for the investigation of preferred crystal orientation and
microstructural defects, applying polarization microscopy of ceramic thin sections and colorimetry.
Polarization microscopy is used in order to visualize the crystal orientation of the single grains.
Different orientations of the optical axes will result in different colors of interference for optically
uniaxial materials. The polarization micrographs themselves are already suitable for the analysis of
the microstructure of CIM components regarding texture, separation planes, etc. Colorimetry is
used in order to measure and describe the colors in a standardized color system. By means of
color/orientation calibration curves that are measured with single crystal references, a quantitative
description of the orientation of single grains as well as texturized areas can be obtained.
Advances in Ultrasonic Assisted Grinding of Ceramic Materials
Authors: Uhlmann E. , Hübert C.
Published: March 2009

The competitiveness of component parts made of advanced ceramics results almost exclusively
from the properties of the material in use. However, it is restricted by the constantly high costs of
part manufacture especially in the finishing stage. The results of recent investigations being
presented in this paper demonstrate an increase in productivity of material removal via the
application of the innovative technology of ultrasonic assisted grinding. During the manufacture of
through holes or grooves in ceramic materials such as Al2O3, Zr2O, SSN and SiC this process is
characterized by significant less process forces and lower process temperatures in comparison with
conventional grinding processes. In order to deepen the process knowledge of this modified
grinding process two different simulation tools have been introduced. A voxel-based approach for
modeling of the material removal as well as CFD-simulation of the unique cooling lubricant flow
conditions proved their capability as an optimization tool.
SiAlON-SiC-Composites for Cutting Tools
Authors: Bitterlich Bernd , Friederich Kilian , Mandal Hasan
Published: March 2009

CeramTec AG is a well-known manufacturer of cutting tool materials, especially for inserts based
on silicon nitride. Some years ago it started the production of alpha/beta-SiAlONs because of their
superior properties. Due to strong competition in the cutting tool business there is a constant need
for further development of the cutting tool materials. One possibility to increase wear resistance and
life time of cutting tools is to increase the hardness and maintaining the good toughness at the same
time. This can be done by adding hard particles like e.g. SiC to an alpha/beta-SiAlON. In 2003 an
improved grade had been presented: a SiC-reinforced alpha/beta-SiAlON. This composite material
shows a significantly reduced wear during machining of cast iron. The effect of SiC-addition on
mechanical and thermal properties is discussed.
Electrochemical Ceramic Device for Hydrogen-Phosphate Ion Sensor
Authors: Shimizu Youichi , Takase Satoko , Yoshida Mariko
Published: March 2009

Novel sol-gel processing techniques of ceramic materials were developed for designing
new functional environmental ion sensors. Wet-chemical preparation methods for metal-oxide
thin-films, perovskite-type oxide thin-films, and solid-electrolyte discs could be developed by using
solution techniques based on polymer precursors, etc. New electrochemical sensing techniques to
hydrogen-phosphate ion with high sensitivity and selectivity were developed by the use of
ceramic-based sensors. A sol-gel processing technique was developed for the preparation of
La-based perovskite-type oxide thin-films using an acetylacetone (AcAc)-modified poly(vinyl
alcohol) (PVA)-based polymeric precursor method. The AcAc modified PVA-based sol made it
possible to deposit a thin-film as well as to lower the sintering temperatures. The La0.8Sr0.2CoO3
perovskite-type oxide thin-film electrode prepared at 500°C showed good properties of
amperometric sensing to hydrogen-phosphate ion. A new solid-electrolyte ion sensor device using a
Na+-ion conductor (Na5DySi4O12: NaDyCON) as an impedancemetric transducer and a
perovskite-type oxide thin-film as a receptor has been further developed. The AC impedance of the
device with a LaCoO3 receptor was found to vary logarithmically with increasing K2HPO4
concentration between 1.0 x 10-5 and 1.0 x 10-2 M at 10 kHz. The 90% response time was ca. 2 min
at room temperature. The sensor showed a little sensitivity to NO3- at higher concentration, while no
response was observed to the examined anions of Cl- and ClO4-.
Ceramic Materials for Mass-Sensitive Sensors - Detection of VOCs and Monitoring Oil Degradation
Authors: Lieberzeit Peter A. , Glanznig Gerd , Leidl Anton , Dickert Franz L.
Published: March 2009

Inorganic frameworks obtained by the sol-gel route can be templated by a molecular
imprinting (MIP) approach to generate functional cavities. Such MIP ceramics show highly
appreaciable properties for chemical sensor applications, because they are inherently chemically
and thermally robust. In combination with mass-sensitive devices (e.g. quartz crystal micro balance
– QCM, surface transverse wave oscillator - STW), they yield highly selective and sensitive
chemical sensors. Gas phase measurements with volatile organic compounds (VOCs) e.g. lead to
sensitivities below 1 ppm. Sensitivity can be tuned by the sol-gel-precursor: when hydrolysing more
bulky alkoxides, this leads to enhanced sensitivity by increasing porosity as a consequence of
slower solvent evaporation. By adding products of oxidative oil degradation to the sol-gel mixture,
we succeeded in generating sensors for degradation processes in these complex matrices. This
allows parallelly monitoring both the chemical state of oil and changes in viscosity. Sensitivity is
enhanced according to the Sauerbrey equation by going from 10 MHz QCM transducers to higher
frequencies either by etching the quartz substrates and so reducing the resonator thickness or by
applying STWs.
Semiconductor Gas Sensors for Environmental Monitoring
Authors: Carotta M.C. , Ferrari E. , Giberti A. , Malagù C. , Nagliati Marco , Gherardi S. , Vendemiati B. , Martinelli G.
Published: March 2009

The main semiconductor oxides for gas sensing have been examined, describing the
synthesis processes and the morphological and structural properties. The powders have been
deposited as thick films through screen-printing technique to achieve gas sensors. The sensing
layers have been studied with regard to semiconductor behaviour, surface barrier potential heights
and gas sensing properties. The interaction of humidity with semiconductor oxides has been
considered with the aim to compensate, using an algorithm, its effect in gas detection. Finally,
nitrogen oxides monitoring, contemporaneously performed in several sites of Italy, has been
described.
Single Chamber Solid Oxide Fuel Cell Using BaLaIn2O5.5 Electrolyte
Authors: Hibino Mitsuhiro , Michiba Dai , Kanatani Kenichi , Suzuki Hiroaki , Yao Takeshi
Published: March 2009

BaLaIn2O5.5 (BLI) is examined as an electrolyte of a single chamber fuel cell using a
mixture gas of methane and air. Power generation of the single cell is investigated with varying
supply rates of methane and air. Furthermore, two cells are connected in series in the single chamber
for high voltage and we evaluate the performance of the system.
Make Hydrogen while the Sun Shines: The Photoelectrolysis of Water Using Oxide Semiconductors
Authors: Rajeshwar Krishnan , Chenthamarakshan C. Raman Nair , de Tacconi Norma R. , Somasundaram Sashikala
Published: March 2009

The principles of photoelectrochemical generation of hydrogen using inorganic
semiconductor/water interfaces are first outlined. Advantages in the use of oxide
semiconductors for solar hydrogen generation are then enumerated. The requirements for the
water splitting reaction in terms of the semiconductor photocatalyst(s) are then elaborated.
Finally, preliminary results are presented on the use of electrodeposited p-Cu2O films for
hydrogen generation in a twin-compartment photoelectrochemical cell using visible light and
sacrificial reducing agents in the (dark) anode compartment.
Thermochemical and Thermophysical Properties of Advanced Fission Fuel Materials
Authors: Minato Kazuo , Takano Masahide , Nishi Tsuyoshi , Akabori Mitsuo , Arai Yasuo , Uno Masayoshi
Published: March 2009

Burning or transmutation of minor actinides (MA: Np, Am, Cm) as well as plutonium is an
option for the future nuclear fuel cycle. For the transmutation of MA, research and development of
MA-bearing fuels that are quite different from the current UO2 and (U,Pu)O2 fuels have to be made.
Among various fuel types, nitride is one of the attractive fuels to the MA-bearing fuel. The
thermochemical and thermophysical properties of nitride fuels available in literature, such as the
thermal expansion, specific heat capacity, thermal conductivity, thermal creep, vaporization behavior,
etc., are briefly reviewed and the new data obtained on actinide nitrides are presented. The thermal
expansion was measured by high-temperature X-ray diffraction, the thermal diffusivity by laser-flash
method, the thermal creep by compression method, Young’s modulus by pulse echo method, and the
hardness by indentation method.
Morphology of Zirconia Nanopowders Crystallised under Hydrothermal Conditions
Authors: Pyda Waldemar
Published: March 2009

Zirconia nanopowders stabilised with 6 mol% calcium oxide were crystallised under
hydrothermal conditions. The effect of pH on chemical composition, phase composition and
morphology of the resultant nanopowders was studied. Behaviour of the nanopowders during
uniaxial pressing and pressureless sintering was characterized. It was found that the solution pH
higher than 10 is required to retain CaO totally in the nanopowder during hydrothermal
crystallisation. Oval nanocrystallites of tetragonal symmetry were obtained as the main phase. An
increase of the solution pH increased both the content and aspect ratio of needle-shaped crystallites
of monoclinic symmetry being the secondary phase. This improved compressibility of the
nanopowders but deteriorated their sinterability and the phase composition of the resultant
polycrystals.
Processing Ceramics for Radioactive Waste Immobilisation
Authors: Lee William Edward , Juoi J. , Ojovan M.I. , Karlina O.K.
Published: March 2009

The basic principles of incorporating high level radioactive waste into glasses,
ceramics and glass composite materials (GCMs) are described. Current UK
technology uses glass wasteforms for the products of reprocessing while some waste
streams may be incorporated in ceramics and difficult or legacy wastes will require
the development of other wasteforms many of which will be GCMs. Processingproperty-
structure relations in novel wasteforms are described including the use of
self-sustaining reactions to produce a composite ceramic wasteform based on TiC and
Al2O3 from irradiated graphite and development of a GCM wasteform for
immobilising spent zeolite sand filters.
Development of Non-Silicate Microporous Membranes with High Chemical Resistance
Authors: Aust Undine , Tomandl Gerhard
Published: March 2009

TiO2-ZrO2 mixed-oxide membranes were prepared via polymeric sol-gel technique. The
final composition is already predefined during the preparation of the sols by using the corresponding
quantities of the starting alkoxides. The mixed-oxide membranes were characterized by Xray
diffraction, nitrogen sorption, and field emission scanning electron microscopy as well as filtration
and corrosion tests. The observed results prove the positive influence on the investigated properties
by addition of a second oxide. Depending on the composition of the mixed-oxide membranes,
a remarkable increase in the crystallization temperatures is demonstrated. Using mixed-oxide systems,
the retardation of grain growth is confirmed.
Elaboration of Superhydrophobic Nanoporous Ceramic Membranes - Application to Desalination
Authors: Larbot A.B. , Gazagnes Laetitia A. , Prouzet E.P.
Published: March 2009

Ceramic membranes are usually elaborated with metal oxides like alumina, titania or
zirconia. These compounds have hydroxyl groups at their surface which give them a hydrophilic
behaviour. In the field of membranes, it can be interesting to use membranes owning a
hydrophobic behaviour. It is the case in the membrane distillation process. This process is based on
a difference of temperature between the feed side and the permeate one. A very convenient method
to change this behaviour is the grafting of particular molecules like fluoromolecules. The grafting
was performed by immersion of the nanoporous membranes in a solution of the fluorinated
compound in chloroform. Immersion time and fluoroalkylsilane concentration are the 2 principal
parameters to be controlled. The characterisation was conduced by TGA, IR and Raman
spectroscopy. The hydrophobic character was determined by measuring the water permeability and
the water contact angle. Contact angles measured on flat samples are in the range 150 - 160°. The
hybrid ceramics are super hydrophobic. Solutions of NaCl and seawater were filtered through the
new membranes. The rejection of salts is total whatever their concentration.
Influence of Slurry Formulation on Mechanical Properties of Reticulated Porous Ceramic
Authors: Negahdari Zahra , Solati M. , Saberi A.
Published: March 2009

Increased processing pressure has resulted in need for the industry to optimize
mechanical properties of ceramic foam filters used for molten metal processing. This paper will
summarize the effect of ceramic slurry formulation on mechanical properties of reticulated
porous ceramics processed by replica method. Commercial polyurethane sponge materials were
chosen as a template to produce the RPC (reticulated porous ceramic) from a shear thinning
multi component aqueous slurry composed of alumina, SiC, colloidal silica and some different
additives. Thermal transformation sequence of the mixtures, resultant macrostructure and
microstructure, relative density, grain morphology, phase composition, and mechanical strength
of the sintered porous ceramics were investigated. Mechanical properties of struts were
investigated by a theoretical model. The RPC had its maximum strength when Alumina/SiC
weight ratio was 4.4. Such materials sintered at 1650° C in air, due to their excellent functional
properties, are suitable for application as molten metal filter.
The Catalysis of NiO-Al2O3 Aerogels for the Methane Reforming by Carbon Dioxide
Authors: Osaki Toshihiko , Mori Toshiaki
Published: March 2009

The aerogels of nickel-alumina system have been synthesized from aluminum
triisoprppoxide and nickel glycoxide by sol-gel and subsequent supercritical drying, and the catalysis
of NiO-Al2O3 aerogels for the methane reforming by carbon dioxide have been examined. The
aerogel catalysts showed higher activity for the reforming than the impregnation catalysts prepared
by a conventional impregnation method, on the other hand, the carbon deposition was much less
significant on the aerogel catalysts than on the impregnation catalysts. By TEM and XRD
observations, it was found for aerogel catalysts that fine nickel particles were formed throughout the
alumina aerogel support with high dispersion. This resulted in not only higher catalytic reforming
activity but also much less coking activity. The suppression of catalyst deactivation during the
reforming was ascribed to the retardation of both carbon deposition and sintering of nickel particles
on alumina aerogel support.
Pore Structure of Alumina Derived from the Alkyl Derivatives of Boehmite
Authors: Kim Sung Wook , Iwamoto Shinji , Inoue Masashi
Published: March 2009

Solvothermal reaction of aluminum alkoxides in various alcohols at 250-300 oC yielded
alkyl derivatives of boehmite (alkoxyalumoxanes; AlO(OH)1-x(OR)x) in which alkyl groups were
incorporated between the boehmite layers through the covalent bondings. In the present work, pore
textures of aluminas prepared by calcination of the products were examined. The alumina obtained
from the ethyl derivative of boehmite had a broad pore-size distribution, while the pore-size of the
alumina obtained from the dodecyl derivative of boehmite distributed in a narrow range in the
mesopore region. The mode pore diameter of the latter alumina increased with the increase in
calcination temperature (600 oC, 39 Å; 800 oC, 54 Å; 1000 oC, 74 Å), but narrow pore-size
distribution was maintained even after calcination at high temperatures.
Synthesis of ZrW2O8 Ceramics and Composites from Aqueous Sol-Gel Precursors
Authors: de Buysser Klaartje , Hoste Serge , Van Driessche Isabel
Published: March 2009

The thermal expansion of a ceramic material in general leads to a positive thermal
expansion coefficient (α). In the last decennium, several families of materials which exhibit
negative thermal expansion, arising from a specific geometrical effect in their so-called open
framework structures, have been discovered. Usually, this negative thermal expansion coefficient is
small, anisotropic and the phenomena occur in a very small temperature interval. ZrW2O8 is an
exception because of its large and isotropic negative thermal expansion coefficient (NTE) in a
temperature range from 0.5K to 1050K. A cubic symmetry is found over the entire stability range
with a phase transition from α-ZrW2O8 to β-ZrW2O8 near 430K. This phase transition is noticed by
a change in α. The aqueous citrate-gel method is a suitable synthesis route for negative thermal
expansion ceramics and will give a fine, pure and homogenous oxide mixture, well suitable for the
preparation of ZrW2O8. The expansion coefficient of α–ZrW2O8 is -11 μm/m K whereas for the β-
ZrW2O8 a value of -3 is obtained.
Improving the Properties of Low Temperature Sintered Alumina Bodies with Granite Reject Additions
Authors: Acchar Wilson , Silveira G.C.L. , de Mello-Castanho Sonia Regina Homem , Segadães Ana M.
Published: March 2009

The use of industrial waste materials as additives in the manufacture of ceramic
products has been attracting a growing interest from researchers in recent years and is
becoming common practice. The continued depletion of natural resources throws a new light
on the potential use of some industrial wastes and natural sub-products as full-fledged
alternative ceramic raw materials. This work describes the research carried out on the low
temperature manufacturing of alumina bodies using, as additive, granite reject as-produced by
an ornamental stone processing industry that saws granite stones into blocks and slabs in Rio
Grande do Norte, Brazil. This reject is produced in significant amounts and is discarded in
sedimentation lagoons, landfill areas or simply thrown in rivers, resulting in environmental
pollution. Samples containing up to 30 wt% granite reject and 5 wt% manganese oxide
(constant) were uniaxially pressed and sintered in air in an electric furnace (1150-1350 °C, for
1 hour). Sintered test pieces were characterized by X-ray diffraction, apparent density, open
porosity and flexural strength. The results showed that the addition of granite reject and
manganese oxide enables low temperature sintering and remarkably improves the cold
mechanical properties of the alumina body.
Synthesis of Gamma-Alumina Nanoparticles by Freeze Drying
Authors: Nieto María Isabel , Tallón C. , Moreno Rodrigo
Published: March 2009

Synthesis by freeze-drying basically consists in rapidly freezing an aqueous salt solution
containing the desired cation and the further sublimation of ice under vacuum conditions. After a
conventional thermal treatment, the oxide nanoparticles are obtained. The influence of the
parameters involved in the synthesis of γ-Al2O3 nanoparticles by a freeze-drying method have been
studied: type of precursor salt (chloride and sulphate), salt solution concentrations (0.76-1.40 M),
freezing rate and thermal treatment.
Amorphous aluminium sulphate spherical granules with diameters ranging from 1 to 100 μm
have been obtained. This compound decomposes at 825°C, leading to the formation of γ-Al2O3.
These porous granules are constituted by soft agglomerates of nanoparticles with primary particle
size lower than 20 nm and values of the specific surface area of 120-180 m2/g. By optimizing the
dispersing conditions a minimum particle size < 30 nm is measured, thus confirming that granules
can be easily dispersed into nanoparticles. The thermal treatment determines the crystalline degree
of the γ-Al2O3 and the surface area. A multimodal porosity is always obtained. The mesoporosity
with mean size of 10 nm, attributed to the interparticulate porosity is practically constant, and the
interagglomerate porosity (100-600 nm) strongly depends on the salt concentration, freezing rate
and thermal treatment of the powders.
On the Plasticity of Clay Mixtures with Bauxite Residue of the Bayer Process
Authors: Pontikes Y. , Angelopoulus G.N. , Kim Ungsoo , Lee H. , Carty William
Published: March 2009

“Bauxite Residue” (BR) is the main waste of alumina-producing Bayer process. With the
aim to use BR in the heavy clay industry, the plasticity of clay mixtures with BR was studied by the
“High Pressure Annular Shear Cell” (HPASC) technique. The information obtained is cohesion and
pressure dependence values that enable the determination of optimal conditions for extrusion. The
results for 30wt% BR addition, substituting the clay mixture, demonstrate that the maximum
cohesion is increased. Nevertheless, the water demand is increased for achieving the appropriate
cohesion and pressure dependence levels for extrusion, a factor that imposes increased demand for
drying. By shifting the particle size distribution towards a higher mean particle size, redesigning the
clay mixture or by polymer addition, the rheological behaviour of the paste can be adjusted.
Influence of Suspensions Rheology on the Properties of Light Weight High Temperature Materials
Authors: Svinka R. , Svinka V. , Bula G. , Juettner T. , Palcevskis E.
Published: March 2009

Light weight materials are produced according to the aerated concrete technology using slurries.
In concentrated suspensions pore formation depends on rheological properties such as viscosity,
zeta potential and pH. The chemical composition as well as the grain size of raw materials and the
sintering temperature have major influence on the pore structure of the final material.
Effect of Thermal Stress on the Microwave Dielectric Properties of (300-X) nm MgTiO3 /(X) nm CaTiO3 Thin Films
Authors: Yoon Ki Hyun , Choi Ji Won
Published: March 2009

The microwave dielectric properties of (300-X) nm MgTiO3/(X) nm CaTiO3 thin films have been
investigated with correlation between the interface and stress induced by dielectric layers with heattreatment.
As the thickness (X) of CaTiO3 film increased, the dielectric constant increased and the
temperature coefficient of the dielectric constant changed from the positive to the negative values
by the dielectric mixing rule. The dielectric loss of (300-X) nm MgTiO3/(X) nm CaTiO3 thin films
increased with an increase of the thickness (X) of CaTiO3 film because of higher thermal stress
induced by the higher thermal expansion coefficient of CaTiO3 than that of MgTiO3.
Microstructural Evolution Model of the Sintering Behaviour and Magnetic Properties of NiZn Ferrite Nanoparticles
Authors: Swaminathan R. , Woods J. , Calvin S. , Huth Joseph , McHenry M.E.
Published: March 2009

The sintering of RF plasma synthesized NiZn ferrite nanoparticles was studied. The
as-synthesized nanoparticles have been modeled as having a core-shell structure with richer Zn
concentration on the surface. Most Zn cations occupy tetrahedral sites typical of zinc ferrites,
while some of the Zn cations occupy tetrahedral sites in a (111) oriented surface layer in the
form of ZnO. Ni and Fe cations show no evidence of such disorder and their positions are
consistent with the bulk spinel structure. This core-shell structure evolves by decomposition of
the as-synthesized nanoparticles into Ni-and Zn-rich ferrites followed by the decomposition of
the Zn-rich ferrites into ZnO and -Fe2O3 during sintering of the nanoparticles. Within the core
region, sintering causes Ni to exit the ferrite structure and be reduced to a metallic form,
possibly via a NiO intermediate. The miscibility gap in the pseudo-binary ZnFe2O4/NiFe2O4
system was modeled using equilibrium solution data. Decomposition rates are interpreted
considering inter-diffusion kinetics. Sintered nanoparticle compacts showed an evolution of a 4-
phase mixture of ferrite + ZnO + -Fe2O3 + Ni with increasing sintering temperature.
The average ferrite nanoparticle size is preserved up to very high sintering temperatures.
These observations suggest that the ZnO shell contributes to the sintering process by surface
diffusion while acting as a barrier to the growth of the ferrite core. Metal edge EXAFS patterns
of the sintered compacts confirm that Fe transforms from a single ferrite phase into a mixture of
-Fe2O3 and ferrite; ZnO content progressively increases with sintering temperature and
elemental Ni evolves from the ferrite with increasing sintering temperature. The saturation
magnetization and Curie temperature were observed to decrease as a function of sintering
temperature, with an anomaly at the temperature where Ni starts to form. This is explained by
Zn diffusing from the core depleting the ferrite and increasing the amount of non-magnetic ZnO
in the shell. AC magnetic measurements also vary systematically with the microstructural
evolution.
A High Throughput Search of Dielectric Thin Films for Tunable Devices
Authors: Choi Ji Won , Kang Chong Yun , Kim Jin Sang , Yoon Seok Jin , Kim Hyun Jai , vanDover R.B.
Published: March 2009

The dielectric properties of (Ba,Sr)TiO3 (BSTO) and Zr doped BSTO thin films have been
investigated to identify candidate thin film dielectric materials having low dielectric loss without
degradation of the tunability by continuous composition spread (CCS) technique using off-axis rf
magnetron sputtering. The optimized properties of BSTO thin films deposited on Pt/SiO2/Si
substrate by CCS were dielectric loss 0.031, tunability 31.5, respectively. The optimized properties
of Zr doped BSTO thin films deposited on Pt/SiO2/Si substrate by CCS were improved by dielectric
loss 42%, FOM 68% at the same BSTO composition, respectively. To confirm the dielectric
properties and compositions by CCS technique, Zr doped BSTO bulk ceramics were evaluated.
Investigation of ZnO Based Thin Films as Resistance Materials with Small Temperature Coefficients
Authors: Sato Yuichi , Goto Makoto , Ikeda Junji , Minakawa Yusuke , Sato Susumu
Published: March 2009

Possibilities of ZnO based thin films for applications as resistance materials with small
temperature coefficients are investigated. The ZnO based thin films containing Cu, Mg, Al and In
are deposited on sapphire c-face single crystal substrates or quartz glass substrates. Resistivities at
room temperature and their temperature dependences of the obtained thin films are measured and
discussed.
Recent Advances in Pyroelectric Ceramics and Thin Films for Applications in Uncooled Infra-Red Sensor Arrays
Authors: Whatmore Roger W.
Published: March 2009

Pyroelectric infra-red detector arrays provide an attractive solution to the problem of
collecting spatial information on the IR distribution in a scene. They have the
property that they are only sensitive to changes in the IR flux. This means that they
are particularly-well suited to the monitoring of movements of people in applications
such as retail outlets and in safety and healthcare applications. The applications of
low cost arrays with limited (few hundred elements) for people sensing and imaging
radiometry will be illustrated. The performances and costs of uncooled pyroelectric
arrays are ultimately driven by the materials used. For this reason, continuous
improvements in materials technology are important. In the area of bulk ceramics, it
is possible to obtain significant improvements in both production costs and
performance though the use of tape-cast, functionally-gradient materials. The use of
directly-deposited ferroelectric thin films on silicon ASIC’s is offering considerable
potential for low cost high performance pyroelectric arrays. The challenges involved
in developing such materials will be discussed.
Comparative Optical Characterization of Transparent Nd-Doped YAG Ceramics and Single Crystals for Laser Applications
Authors: Sani E. , Favilla E. , Ciofini M. , Lapucci A. , Bezzi G. , Mingazzini C. , Sangiorgi S.
Published: March 2009

Highly-transparent Nd:YAG ceramic pellets have been produced, characterized and
compared with Nd:YAG commercial ceramics and single crystals. The obtained results are
promising for laser applications.
Vanadium Doped Antimony-Tin Oxide Nano-Sols and their Films Produced by a Sol-Coating Method
Authors: Jeon Seong Je , Lee Jai Joon , Kim Jun Tae , Koo Sang Man
Published: March 2009

Ethanol-based antimony-tin oxide (ATO) and vanadium-doped ATO (V-ATO) nano-sol
solutions were prepared in H2O containing tetramethylammonium hydroxide by peptizing their
coagulated precipitates which were synthesized by hydrothermal reaction at 170°C in an autoclave.
Also, the ATO and V-ATO films were formed by spin coating to be investigated with dopants (V, Sb)
and solid content on their conductivity and transparency.
Experimental Study and Modelling of Combustion Front Velocity in Ti-2B and Ti-C Based Reactant Mixtures
Authors: Martinez Pacheco M. , Bouma R. , Arias Cuevas O. , Katgerman Laurens
Published: March 2009

Experiments on combustion synthesis for the Ti-2B and Ti-C systems diluted with an
inert metal are presented. The paper shows the influence of geometry, composition, density and
particle size of diluent on the combustion front velocity. A Ti-2B reactant mixture diluted with Al
and Cu and a Ti-C reactant mixture diluted with Al are studied. The metallic diluent and its
concentration are varied. Besides, each experiment is based on a stack of cylinders with decreasing
diameter in order to vary the heat losses. In some experiments the eventual quenching of the
combustion reaction has been observed. Furthermore these experimental results are compared with
theoretical calculations based on analytical expressions derived for such systems.
Preparation of Nano-Sized TiO2 Particles by Self-Propagating-High-Temperature Synthesis
Authors: Wang C.M. , Chung S.L.
Published: March 2009

This investigation was aimed at preparing nanocrystalline TiO2 powder by
self-propagating-high-temperature synthesis. Titanium (IV) n-butoxide was hydrolyzed to
obtain titanl hydroxide [TiO(OH)2], and titanyl nitrate [TiO(NO3)2] was obtained by reaction
of TiO(OH)2 with nitric acid. Finally, the aqueous solution containing titanyl nitrate
[TiO(NO3)2] and a fuel, urea, were mixed and combusted to obtain the nano-sized titania. The
anatase TiO2 nanocrystalline ( ~56nm) with high BET surface area( 280 m2g-1) and narrow
band gap energy( 2.7 eV) were thus obtained.
Laser Synthesis of Oxide Nanopowders
Authors: Ivanov M. , Osipov V. , Kotov Yu. , Lisenkov V. , Platonov V. , Solomonov V.
Published: March 2009

Oxide nanopowders Y2O3, ZrO2, YSZ (Y2O3-stabilized ZrO2), Ce0.8Gd0.2O2 and Y2O3-
Al2O3 compounds were prepared with the help of laser evaporation and subsequent vapor
condensation in the flow of buffer gas. An efficient technology and setup to produce high purity
weakly agglomerated nanopowders are demonstrated. The output rate, alteration of elemental
composition, size distribution and crystalline structure of the nanopowders depending on
parameters of laser radiation and buffer gas flow are reported.