bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization and Performance of Glass-Ceramic Sealants for SOECs
Authors: Khedim Hichem , Connelly Andrew J. , Nonnet Hélène , Coillot Daniel , Mear François , Montagne Lionel
Published: October 2010

Research into hydrogen production using high temperature electrolysis methods has
increased significantly in the last few years. Consequently, development of sealing materials has
become a major concern particularly for developers of Solid Oxide Electrolyser Cells (SOECs).
Suitable sealants for SOECs must operate around 800°C for many hours under reducing and
oxidizing conditions. Glass-ceramic compositions based on two glass systems CAS (CaO-Al2O3-
SiO2) and SCAS (SrO-CaO-Al2O3-SiO2) with some minor additions (MnO2, B2O3 or TiO2) have
been prepared and investigated. Thermal, chemical, and physical properties of the glass ceramics
were examined along with the glass crystallization behaviour. Hot Stage Microscopy allowed
observation of the sintering and wetting behaviour of glass-ceramics and showed it to be a complex
process, significantly affected by glass composition, viscosity, glass transition temperature,
crystallization rate and the nature of the crystalline phases formed. The bonding characteristics of
parent glasses with ceramic and/or metallic interconnector were observed under air at the cell
operating temperature. The results revealed the most suitable glass-ceramic compositions to meet
the different criterions and the difficulties involved in formulating such materials.
Ultrarapid Transient-Liquid-Phase Bonding of Advanced Ceramics
Authors: Hong Sung M. , Bartlow Christopher C. , Reynolds Thomas B. , Saito Noritaka , Glaeser Andreas M.
Published: October 2010

Interlayer designs and processing conditions that promote rapid and reliable transientliquid-
phase (TLP) bonding/joining of Al2O3 and ZrO2-toughened Al2O3 ceramics are presented.
The interplay between wetting, roughness, interlayer design and microstructure, and interlayer
homogenization is described. The prospects for extending the method to other ceramics, notably the
ultrahigh-temperature ceramics (UHTCs) will be discussed.
Processing and Characterization of Zr-, Hf- and Ta-Based Ultra High Temperature Ceramics
Authors: Licheri Roberta , Orrù Roberto , Musa Clara , Cao Giacomo
Published: October 2010

The fabrication of MB2-SiC and MB2-MC-SiC (M=Zr, Hf, Ta) Ultra High Temperature Ceramics (UHTCs) is investigated in this work by combining Self-propagating High-temperature Synthesis (SHS) and Spark Plasma Sintering (SPS). Zr, Hf or Ta, B4C, Si, and graphite powders are first reacted by SHS to successfully form in-situ the desired composites. For the case of the Tabased systems, a 20 min ball milling treatment is also required to mechanically activate the SHS reactions. The resulting powders are subsequently consolidated by SPS at 1800 °C and P=20 MPa, thus obtaining products with densities greater than 96% within 30 min of total processing time. Hardness, fracture toughness, and oxidation resistance of the resulting dense UHTCs are among the best when compared to the corresponding values reported in the literature relative to analogous products synthesized by alternative, more energy-consuming and less rapid methods. Thermogravimetric analysis results evidenced the beneficial effect of SiC on the oxidation resistance of the composite materials, while the presence of transition metal carbides appears to be inconvenient from this point of view. This is because, they rapidly oxidize at high temperature to form MxOy and carbon oxides which lead to an increase in sample porosity thus enhancing product oxidation.
Oxidation Mechanism of ZrB2-SiC Tested in a Solar Furnace above 2200°C
Authors: Andreani Anne-Sophie , Rebillat Francis , Poulon-Quintin Angéline
Published: October 2010

The solar furnace is a heating system based on concentrated sunrays on the material
surface. It is an original method for testing ultra-high-temperature ceramics (UHTC) at very high
temperature (above 2200°C) in air with an exposure time of several minutes. In this study, the solar
flux is 15.5 MW.m-2 with a homogeneous exposed surface of 10 mm2. A large temperature-time
composition parameters space is covered producing a large set of oxidized samples. Massive
cylindrical specimens of UHTC materials are prepared by spark plasma sintering at 1900°C under a
pressure of 100 MPa for 5 minutes. Then, samples are tested in air from 1750°C up to 2400°C with
dwell times varied from 1 to 5 min. During oxidation of ZrB2-SiC (20%vol) material, the formed
and known complex oxide scale identified from literature is easily reproduced using this method. It
consists of a thin outer silica layer and zirconia columnar layer with a region of SiC depleted zone
in ZrB2 phase. The impact of the reduction of Si content is quantified and the coating ZrB2-20%vol
SiC is tested as protection on C-C composite.
Metal Oxides (such as Al2O3 and TiO2) as Catalyst Supports for Hydrogen Release by Hydrolysis of Sodium Borohydride NaBH4
Authors: Akdim Ouardia , Demirci Umit Bilge , Miele Philippe
Published: October 2010

Hydrolysis of NaBH4 to release molecular hydrogen is today an intensely investigated
reaction and most of the studies focus on the material used as catalyst. Among the various metals
tested up to now, cobalt has soon showed to be the most attractive in terms of reactivity and cost.
Nevertheless, in order to further decrease its cost by decreasing its amount as well as to increase its
reactivity, cobalt has been dispersed over supports. The as-formed supported catalysts have showed
to be more efficient. This is the topic of the present study. Herein it is showed that CoCl2 supported
over an Al2O3 support with a specific surface area of 180 m2 g-1 is more reactive than CoCl2
supported over a high-surface-area activated carbon (780 m2 g-1), CoCl2 being in-situ reduced into
the Co-based active phase. CoCl2-Al2O3 is besides as reactive as another CoCl2-Al2O3 catalyst, the
latter support having a higher specific surface area (i.e. 250 m2 g-1). In fact, CoCl2-Al2O3 is more
performing than neat CoCl2 whereas the latter has been often showed as being one of the best
catalytic systems. To further gain in reactivity, a new, alternative strategy has been envisaged. The
Al2O3 was mixed together with a controlled amount of another oxide, namely TiO2. The CoCl2-
Al2O3-TiO2(20 wt%) was found to be more reactive than CoCl2-Al2O3. All of these reactivity data
are reported and briefly discussed hereafter. Further studies are in progress to highlight the reasons
of such improved reactivity.
Thermal Residual Stresses Generated during Processing of Cr-Al2O3 Composites and their Influence on Macroscopic Elastic Properties
Authors: Weglewski Witold , Chmielewski Marcin , Kaliński Dariusz , Pietrzak Katarzyna , Basista Michal
Published: October 2010

This work is focused on the modeling of thermal stresses induced during the fabrication
of the metal/ceramic composites. On example of Cr-Al2O3 composite processed by powder
metallurgy, thermal stresses after fabrication are determined by FEM model for different contents of
metal and ceramic phases. Numerical model of microcracking induced by thermal stresses is then
proposed and applied to compute the overall elastic properties of the damaged composite.
Comparison of the model predictions with the measured data for Young's modulus is presented.
Hot Rolling Steels and Super Alloys with Silicon Nitride Tools
Authors: Danzer R.
Published: October 2010

Tools for rolling steels and super alloys, which are nowadays in general made from steel
or cemented carbides, suffer from wear and/or from surface cracking caused by thermal fatigue.
New tools made from silicon nitride show improved performance in respect to thermal shock
loading and wear. But their low toughness manifests also a high risk of brittle failure. Nevertheless
the successful use of silicon nitride rolls with having more than a manifold lifetime (compared to
the conventional solutions) has been reported in the last years [1 -3].
In this paper earlier work of the Institut für Struktur- und Funktionskeramik at Montanuniversität
Leoben on highly loaded silicon nitride rolls is summarized, where the limits of the Application of
silicon nitride rolling tools are discussed. On the extreme example of rolls for super alloy wire
rolling the behaviour of small surface cracks in the roll track is discussed. It is shown that – for the
investigated conditions - rolling high strength steel wires is manageable but rolling of super alloy
wires will cause the growth of fatigue cracks, which may destroy the rolls after some tons of rolled
wire.
A not trivial problem to be solved is the connection of the ceramic tool with the metal parts of the
roll stand. Thermal strains of the metal parts can be several times larger than those of the silicon
nitride ceramic and can therefore cause very high thermal misfit strains, even if the heating of metal
parts seems to be modest. This case is discussed on the example of a catastrophically failed ceramic
tool. This clearly shows that not only the tool but also the joint of the tool to the rest of the
machinery has to be designed carefully.
In summary this work demonstrates that a successful use of silicon nitride ceramic tools for cold
and hot forming of metals and alloys is possible.
Easy-to-Clean Coatings on Glass and Glazed Surfaces
Authors: Piispanen Minna , Kronberg Thomas , Areva Sami , Pimenoff Joe , Hupa Leena
Published: October 2010

Glass and glazes are easy-to-clean surfaces often used in everyday environments where the surface needs to repel soils and deposits. In general, these surfaces have good chemical durability in everyday environments. However, the durability is rapidly degraded in solutions of high or low pH. This kind of surface corrosion has been found to diminish the cleanability. Surface topography has also a certain influence on the soil attachment and cleanability. Self-cleaning and easy-to-clean coatings have been employed to enhance the cleanability of surfaces. In this report surface properties of three coatings reported to enhance the cleanability of glass and glazed surfaces are summarized. The properties discussed are the surface appearance, roughness, wettability, soil attachment and soil removal. Also the chemical and mechanical durability of the coatings are discussed. The coatings studied were a commercial fluoropolymer film applied at room temperature, an experimental sol-gel derived TiO2 coating calcined at 500°C, and an experimental liquid flame sprayed TiO2-Ag coating applied on the substrates at 500-800°C. The advantages of the fluoropolymer coating are easy application and soil good soil repellence, but the coating has limited chemical and mechanical durability. The manufacture of the sol-gel TiO2 coating requires several processing steps. The coated surface showed excellent cleanability, and good chemical and mechanical durability. The liquid flame sprayed coating has potential to be applied online in the material manufacture. However, the processing parameters should be optimized in order to achieve desired improvements in the cleanability.
A Chemometric Study of Alumina/PEEK and Hydroxyapatite/PEEK Suspensions Prepared for Electrophoretic Deposition of Multifunctional Coatings
Authors: Martina Virginia , de Riccardis M. Federica , Carbone Daniela
Published: October 2010

Poly(etherether-ketone) (PEEK) suspensions in ethanol and isopropanol containing also
α-alumina and hydroxyapatite powders were studied. An innovative method was used in the study
of the quality of suspensions. We studied suspensions by means of zeta potential and grain-size
measurements. The comparison amongst the different suspensions was carried out by using
statistical and chemometric tools, especially by the use of an explorative test based on the Principal
Component Analysis (PCA). The chemometric analysis was performed by involving different
combinations of each type of powder and each type of solvent.
Dielectric Behavior of YMnO3 Epitaxial Thin Film at around Magnetic Phase Transition Temperature
Authors: Maeda Kazuhiro , Yoshimura Takeshi , Ashida Atsushi , Fujimura Norifumi
Published: October 2010

Relationship between magnetic ordering and ferroelectric polarization switching in YMnO3 epitaxial thin film was investigated. It was found that Néel point of the YMnO3 film is below 80 K, which is consistent with that of YMnO3 single crystal by neutron diffraction. From temperature dependence of the polarization-electric field hysteresis loops and the dielectric permittivity-voltage characteristics, ferroelectric polarization switching behavior was investigated from 300 to 10 K in detail. The ferroelectric polarization switching behavior accords with Ishibashi-Orihara’s theory. Moreover, it was found that the dielectric permittivity under bias electric field have a anomaly below 80 K and the nucleation density for the ferroelectric polarization switching decreases below 130 K, which is higher than 80K.
Sintering Behaviour of Ceramics Containing Paper Sludge, Glass Cullet and Different Types of Clayey Materials
Authors: Furlani Erika , Tonello Gabriele , Maschio Stefano , Aneggi Eleonora , Minichelli Dino , Bruckner Sergio , Lucchini E.
Published: October 2010

The sintering behaviour of several ceramics prepared using a previously selected mixture of incinerated paper mill sludge and glass cullet which was blended with 10, 20, 30 and 40 wt% of some natural clayey materials has been studied. Three natural commercial product were used: a red clay, a yellow clay and a kaolin. Mixtures were blended by wet attrition milling, dried, sieved, pressed into specimens and then fired for 1 h at temperatures ranging from 1040 to 1140 °C. The resulting materials were characterized by water absorption, shrinkage and crystallographic composition. It was observed that materials containing kaolin display the best overall behaviour independently of the quantity of kaolin introduced. Conversely the optimal sintering temperature, and consequently the best properties of materials prepared using red or yellow clay was found above 1080 °C and depends of their specific composition being affected by the amount of clay added.
Colour Properties of Y2O3-Al2O3-Cr2O3 Pigments as a Result of Precursors Morphology
Authors: Stobierska Ewa , Bućko Mirosław M. , Lis Jerzy , Kuźmińska Katarzyna
Published: October 2010

Double yttrium-aluminium oxide with perovskite structure (YAP) doped with chromium(III) ions seems to be a promising material for red pigments for new ceramic bodies and glazes. The aim of the present paper was to examine the influence of the precursors morphology on colour properties of the YAP pigments. Two kinds of aluminium hydroxide powders were used, fine- and coarse-grained. The fine Al(OH)3 powder was amorphous with D50=4.58 µm and the coarse one was crystalline gibbsite with D50=42.4 µm. It was stated that using of aluminium hydroxide powders of different morphology led to substantial differences in phase composition of the final materials. Using coarse-grained aluminium hydroxide powder caused formation of over 95 wt% of YAP phase whereas the pigments prepared with amorphous aluminium hydroxide contain significant amounts of other phases in the Y2O3-Al2O3 system. The differences in phase compositions resulted in differences in colour properties of the pigments.
New Chromium-Calcium Titanate Red Ceramic Pigment
Authors: Gargori Carina , Galindo Roberto , Llusar Mario , Cerro Sara , García Araceli , Monrós Guillermo
Published: October 2010

synthesis and characterization of a new chromium- calcium titanate red ceramic pigment is described in this communication. The pigment is based on the solid solution of chromium (IV) in calcium titanate and was characterized as red-brown pigment in a CaO-ZnO-SiO2 transparent glaze used for ceramic tiles (1080°C). XRD, UV-Vis-NIR spectroscopy and CIE-L*a*b* techniques of characterization have been employed. The L*a*b* valour of the optimal pigment with 0,015 mol/mol of chromium fired at 1100°C with a soaking time of 3 hours and 5% weight added to the transparent glaze is 59.3/12.5/9.5. Likewise 5%w. addition of NHCl used as flux agent increase b* and decrease L* valour (L*a*b*=45.2/15.3/5.3).
The Effect of Ferrochromium Fly Ash as a Pigment on Wall Tile Glaze
Authors: Bayer Öztürk Zahide , Ay Nuran
Published: October 2010

Fly ash is a waste of ferrochromium production which contains high amount of Cr2O3 and Fe2O3. In this study, fly ash was incorporate into pigment recipe for the purpose of coloring due to its high Cr2O3 and Fe2O3 content. Pigments were produced by using Cr2O3, Fe2O3, CoO and fly ash, added to glaze composition at different ratios (wt. 1-5 %). Glazes were applied on ceramic tiles and fired at 1145 °C/ 30 min. Glazed tiles were analyzed by using Autoclave, Harcourt and color measurement tests. Increasing of fly ash content in glaze, the color of glaze changed from brown to grey. The results of Autoclave and Harcourt tests of glazed tiles meet the requirement. This data shows that the fly ash could be used as color additives in glaze.
Synthesis of Hybrid Lamellar Silica by Liquid Crystal Templating and Silanation
Authors: Toussaint Gilles , Henrist Catherine , Vertruyen Bénédicte , Cloots Rudi
Published: October 2010

This paper is focused on the preparation and characterization of different lamellar silica
prepared by liquid crystal templating and silanisation. The initial template can be removed and
replaced in the interlamellar spaces by different types of silane, being covalently grafted to the solid
by reaction with the surface silanols. The lamellar stacking periodicity remains after this
modification. The surfactant extraction can lead in significant grafting of isopropanol if the solid is
simply refluxed in isopropanol, which have the effect of preserving the periodicity of the lamellar
stacking. The surfactant extraction in an Soxhlet equipment avoid this reaction, with the effect of
platelets organization collapsing. The lamellar silica studied exhibit great specific surface and
combination of meso and microporosity, making them interesting materials for nanocomposite or
catalysis applications.
Long-Term Optical and Thermal Examinations of Ceramic Wall System with Solar-Altitude Dependent Reflectance
Authors: Kakiuchida Hiroshi , Tazawa Masato , Sugiyama Toyohiko , Yoshimura Kazuki , Tajiri Koji , Ishikawa Yukio
Published: October 2010

Many ceramic tiles are used as outer skins of office and residential buildings and they
prevent severe weathers of solar ray, temperature, wetness and wind. The solar irradiance to the outer
walls is a significant factor to influence the heat flow into room and consequently the energy load due
to air conditioning. Particularly in the region where clear seasonal change is experienced, optical and
thermal properties of the wall surfaces are desired to be controlled as a function of season; solar
reflective in hot days in summer; solar absorptive in chilly days in winter. The ceramic walls with
solar-altitude dependent reflectance are expected to be a simple and efficient method for autonomous
control of heat flow into the room and in this study they were investigated from the viewpoints of
optical property and shape of the tiles. The correlation between solar absorption and luminous
reflectance revealed that there are some ceramic tiles whose solar absorption slightly depends on
solar altitude. The triangular-shaped ceramic tiles that have reflective-upward and
absorptive-downward surfaces were investigated in optical and thermal properties, based on one-year
exposure of the tiles to solar radiation and ray-tracing simulation. These measurement and simulation
found that the triangular-shaped tiles are an effective approach to the control of solar absorption and
suggested the effective shape and surface property of the tiles such as optical reflectance, surface
specularity and triangular angle.
New Geopolymers Based on Electric Arc Furnace Slag
Authors: Bignozzi Maria Chiara , Barbieri Luisa , Lancellotti Isabella
Published: October 2010

Electric arc furnace slag (EAF-S), coming from a steel productive plant in Italy, has been
used as new source for geopolymers synthesis. The slag has been geopolymerized alone and with
different content of metakaolin (MK) with the aim to investigate if EAF-S content plays a role in
geopolymerization process. Mechanical properties results and microstructure analysis highlight that
the optimum weight ratio MK/EAF-S to be used as starting materials is 40/60, 30/70, 20/80.
Moreover EAF-S, when used with MK, directly participates in the formation of calcium-rich
alumino-silicate gels.
How to Assess the Environmental Sustainability of Geopolymers? A Live Cycle Perspective
Authors: Weil Marcel , Buchwald Anja , Dombrowski-Daube Katja
Published: October 2010

Geopolymers as an alternative binder system gains growing attention in research and
development. Outstanding technical properties like high strength, high acid resistance, or high
temperature resistance can be unerringly achieved. Thus geopolymers are not only suitable for the
development of building products, but are also interesting binder systems for ceramic applications.
Besides the technical performance of geopolymers, which is well investigated, only limited
scientific knowledge exists about the environmental sustainability of geopolymers [1].
Due to the wide range of suitable raw materials and hence resulting, different geopolymer
compositions for distinct application fields a generally statement about the environmental
implications cannot be addressed to geopolymers. A more detailed analysis and assessment is
needed, to provide more diversified statements.
Understanding Study of Silicate Based Gel Formed during the Setting Ceramic Materials
Authors: Tognonvi Monique Tohoué , Rossignol Sylvie , Bonnet Jean Pierre
Published: October 2010

Consolidation of cementitious and geopolymeric materials involves silicate-based gel formation. This in situ mechanism is difficult to identify because it occurs in a complex and developing system representing only a minority phase. A study based on the behaviour of acidified sodium silicate solutions in alkaline medium, was therefore initiated in order to define the conditions of irreversible setting. A concentrated sodium silicate solution ([Si]=7 mol/l, pH=11.56, Si/Na=1.71) was used as starting solution. 29Si NMR spectroscopy, SAXS and elementary chemical analyses (ICP-AES) were used to characterize the various solutions.
Acidification of initial solution, leads in a range of relatively low pH and silicon concentration to various gels formation: (i) reversible transparent gels made up of aggregates of particles (Si7O18H4Na4) and which do not change over time, (ii) soluble white gels that lead to gradual formation of a soluble solid consisting of colloid composition of NaSi1.87O4.24, (iii) “irreversible” gels which provide a syneresis phenomenon leading to formation of a strongly consolidated solid made up of soluble phase rich in sodium similar to white gels (NaSi1.87O4.24) and an insoluble phase type silica of composition NaSi12.66O25.82.
Use of Sodium Silicate Gel as Precursor of Binder for Cold Consolidated Materials
Authors: Tognonvi Monique Tohoué , Kouassi Séka Simplice , Maeda Toyotaka , Soro Julien , Rossignol Sylvie , Bonnet Jean Pierre
Published: October 2010

Consolidation of cements and geopolymers can be explained by the formation of alkali
silicate or alumino-silicate gels formed in situ during materials setting. To control such a system, a
study concerning the use of sodium silicate gel as binder was initiated to manufacture consolidated
materials with different size distribution of silica. The gels used as precursor of binder were
synthesised by acidifying with hydrochloric acid, a concentrated sodium silicate. Consolidated
materials were obtained by mixing the previous solution before gelation with granular materials
(fine silica powder and sands).
The existence domain of consolidated materials depends on the size distribution of sand.
Consolidation of material is strong when the amount of silica is high. This result suggests a
dissolution / precipitation reaction between gel and silica. Therefore, consolidation could be
explained by the dissolution of small particles of silica and their precipitation into the grain
boundary of sand. Mechanical properties are closed to those of cement materials.
Sintering Studies on Magnesia-Rich Chromium-Free Spinel-Bonded Basic Refractories
Authors: Lodha Rahul , Oprea Carmen , Troczynski Tom , Oprea George
Published: October 2010

Basic bricks with Cr2O3 from chrome ore, as the spinel forming oxide, are used in the non-ferrous
industry because of their corrosion resistance against fayalite-type slags, rich in FeO. Our objective in this
study was to replace Cr3+ with Me4+ ions, which along with Fe3+ could maintain the spinel formation
capability with MgO and perform similarly against fayalite slags in non-ferrous furnaces. Our preliminary
research studies showed that Cr-free spinels in the MgO-Al2O3-FeOx-Me4+O2 systems could perform against
fayalite slags similar to the complex (Mg2+, Fe2+)O·(Cr3+, Fe3+, Al3+)2O3 spinel, the main corrosion resistant
component in the magnesia-chrome bricks. The incorporation of iron oxide in the MgO-Al2O3-Me4+O2
systems would contribute to reactive sintering and also in decreasing the solubility of both the ferrous and
ferric ions present in the fayalite slag. Phase analysis on stoichiometric mixes showed that the use of
tetravalent cation oxides like tin dioxide (SnO2) and titanium dioxide (TiO2) can induce high solubility of
spinel in magnesia. In order to maintain charge balance, two trivalent cations were replaced by a tetravalent
and a bivalent cation causing the additional bivalent cation to occupy the octahedral position thereby creating
an inversion in position of the bivalent ions similar to the behaviour exhibited by Fe3+ occupying tetrahedral
site in complex spinel phase of magnesia-chrome ceramics. Most of the magnesia-chrome refractories have
~60 wt. % MgO and hence our experimental mixes contained that amount and called “magnesia-rich”
compositions, to be distinguished from the stoichiometric MgAl2O4 spinel. Our findings showed that the
incorporation of nano TiO2 powders reduces the temperature of spinel formation as the diffusion path is
shortened and thus activates both synthesis and sintering. Compositions containing 60 wt. % magnesia with
alumina, nano TiO2 and Fe2O3 fired below 1500°C for 3 hours resulted in complete spinel formation and
open porosity less than 5%.
Novel Magnesia Carbon Slide Gate Refractory Material for Corrosive Steel Application
Authors: Ziemnicki Mariusz , Rezaie Alireza , Snyder Mark , Desai Priyadarshi
Published: October 2010

Slide gates are used to control the flow rate of molten steel in continuous casting. The properties
that are important for materials for slide gate application are corrosion resistance, thermal shock
resistance, abrasion resistance, and strength. However, operating conditions and in particular steel
chemistries vary by shop and require development of different refractory material qualities.
Alumina-carbon refractories are the prevalent family for slide gate application due to their superior
thermo-mechanical properties. However, they suffer from extensive corrosion in aggressive
applications. On the other hand, magnesia based refractories show promising corrosion resistance,
but they are poor in terms of thermal shock and abrasion resistance. A novel approach using
material based solution was employed to utilize a combination of properties of both refractory
material families. This approach resulted in a material composite that jointly exhibits the thermomechanical
properties and abrasion resistance of alumina based refractory and the corrosion
resistance of magnesia based refractory. This paper will present the properties, key limiting factors,
and results of usage at three steel plants.
Selection Criteria and Tools for Refractory Materials to Be Used in Pulverised Coal Combustion (PCC) Reactors
Authors: Miceli Patrizia , di Donato Antonello , Martini Umberto
Published: October 2010

Criteria and tools are presented for the selection of appropriate refractory materials to be
used in pulverised coal combustion reactors for the production of electrical energy. One of the main
causes of failure of refractory materials is the high temperature corrosion due to chemical attack of
the slag formed from the coal ash and possible additives. Selection criteria are based on the
phenomena involved in the corrosion mechanism. The developed tools are based on
thermodynamics of chemical reactions between oxides systems and permitted to evaluate the classes
of materials in terms of chemical corrosion resistance as a function of slag composition and
temperature. The effects of the chemical interaction between slag and refractory on the physical and
chemical properties of the slag, such as viscosity, melting point, change of composition, solid phase
formation, were also investigated. Experimental tests resulted in agreement with the indications
obtained from the thermodynamic evaluation. Preliminary evaluation is an important tool for
reducing the number of laboratory trials often expensive and time consuming. These chemical
aspects are complementary to the engineering plant aspects and must be taken into consideration for
a successful realization of the process.
Investigation of Refractory Corrosion of a Gas-Stirred Steel Ladle by Simulation
Authors: Vollmann Sandra , Harmuth Harald
Published: October 2010

The present work aims the calculation of the mass transfer coefficient in the slag bath area of a gas-stirred steel ladle. The mass transfer in dependence on influencing factors like flow rate and velocity of purging gas was investigated. For this purpose computational fluid dynamics calculations were performed. Due to the fact that during refractory corrosion diffusion-controlled mechanisms take place simulations considering diffusion were performed. From the resultant concentration of the diffusive component in the slag in dependence on time the mass flux is known. With the help of Fick´s 1st law that describes the diffusive mass flux the mass transfer coefficient may be calculated. From a dimensional analysis followed by a parameter study conducted with the help of computational fluid dynamics calculations a relation for the mass transfer in the slag bath area of the gas-stirred steel ladle was deduced.
Er3+/Yb3+/Ce3+ Co-Doped Fluoride Glass Ceramics Waveguides for Application in the 1.5µm Telecommunication Window
Authors: Boulard Brigitte , Alombert-Goget Guillaume , Savelii Inna , Duverger-Arfuso Claire , Gao You Ping , Ferrari Maurizio , Prudenzano Francesco
Published: October 2010

Er3+-doped fluoride glass ceramics planar waveguides containing LaF3 or binary LaF3-
ZrF4 nanocrystals have been fabricated by Physical Vapour Deposition (PVD). A quantitative
analysis of the photoluminescence for the 1.5μm emission band of Er3+ ions has demonstrated that
erbium ions are partitioned in both crystals and vitreous phase; the solubility of Er3+ in the
segregated LaF3 nanocrystals can reach 30 mol% and the emission bandwidth has been found to be
greater than that of the precursor glass (71nm at the half-height width). In order to increase the
luminescence of Er3+, codoping with Yb3+ and Ce3+ has been investigated. The high Er3+
concentration and spectral width could make this nanostructured fluoride material suitable for
planar amplifier in the C telecommunication band.
Preparation of PVA/ Sm(NO3)3-Sm2O3 Composites Nanofibers by Electrospinning Technique
Authors: Frontera Patrizia , Busacca Concetta , Modafferi Vincenza , Antonucci Pierluigi , Lo Faro Massimiliano
Published: October 2010

. In this work PVA/Sm2O3 composite fibers and Sm2O3 fibers (PVA and Sm(NO3)3 were used as precursors) were prepared by using electrospinning technique. The fibers obtained were characterized by scanning electron microscopy, X-ray diffraction, thermogravimetric analysis and Fourier transform infrared spectroscopy.
Thermal Conductivity of Ceramic Nanocomposites – The Phase Mixture Modeling Approach
Authors: Pabst Willi , Hostaša Jan
Published: October 2010

In nanocrystalline materials the grain boundaries must be considered as regions of finite thickness with properties different from the crystalline bulk material present in the crystallite cores. Thus, dense (i.e. pore-free) single-phase nanocrystalline materials can be considered as quasi-twophase systems whose effective properties can be calculated when quantitative thickness information is available and the property value of the grain boundary phase can be reliably estimated. Similarly, dense two-phase nanocomposites may be considered as quasi-three-phase systems and their effective properties can be predicted using an analogous phase mixture modeling approach. In this contribution this is done for the thermal conductivity of alumina-zirconia nanocomposites. A twostage homogenization procedure is applied, consisting of a first step in which the alumina-zirconia composite is treated as a symmetric-cell material, and a second step in which the highly disordered grain boundary phase is treated as a matrix-phase, coating the crystallite cores. The individual averaging steps are discussed with respect to the two- and three-point bounds, and the resulting grain size dependence is compared with that of pure alumina and zirconia, and literature data.
Feasibility of Liquid Fuels for SOFC with Ni-Base Anode
Authors: Kishimoto Haruo , Yamaji Katsuhiko , Brito Manuel E. , Horita Teruhisa , Yokokawa Harumi
Published: October 2010

Degradation and disintegration of the nickel base cermet anode is a serious problem in direct utilization of hydrocarbon fuels, especially for liquid fuels such as kerosene. Cell operation test was carried out for the SOFC with nickel – scandia stabilized zirconia (Ni-ScSZ) cermet anode by direct feeding of several liquid hydrocarbons at 1073 K at S/C = 2.0. For n-dodecane (C12H26) fuel, hydrogen produced by reforming reaction on the anode was mainly used for electrochemical oxidation reaction. In contrast, for desulfurized kerosene test, cell operation was only possible by lower current density. Furthermore, noticeable nickel particles growth occurred. This nickel sintering should be enhanced by remaining minor impurities, including sulfur, in the desulfurized kerosene. From the thermodynamic consideration, Ni-S eutectics can be stably formed under some SOFC operation conditions with 100 ppm of sulfur. Carbon deposition was observed on the nickel surface for both Ni-yttria stabilized zirconia (YSZ) and Ni-ScSZ systems, but was noticeably suppressed for Ni-gadolinia doped ceria (GDC) system.
A Novel Anode Based on Ni-Modified Perovskite for Direct Alcohol Solid Oxide Fuel Cells
Authors: Lo Faro Massimiliano , Monforte Giuseppe , Stassi Alessandro , Minutoli Maurizio , Antonucci Vincenzo , Modafferi Vincenza , Antonucci Pierluigi , Arico’ Antonino Salvatore
Published: October 2010

A Ni-modified La0.6Sr0.4Fe0.8Co0.2O3 / Ce0.9Gd0.1O2 catalyst was prepared by incipient wetness. The product thus obtained was calcined at 1100°C for 2 h in static air. After thermal activation, Ni was mainly present as highly dispersed La2NiO4 on the surface of perovskite surface. The thermal reduction at 800 °C caused the occurrence of metallic Ni on the surface. Surface area was determined by BET measurement. The catalyst was used as anode in IT-SOFCs fed with methanol. Studies under steam reforming, partial oxidation and autothermal reforming of methanol were carried out at 800°C. A comparison was made between the performance of SOFCs fed with syngas or methanol. The results with methanol are promising both in terms of energy density as well as suitable performance for portable power sources.
Elaboration and Characterization of the Properties of Refractory Cr Base Alloys
Authors: Royer Laurent , Mathieu Stéphane , Liebaut Christophe , Steinmetz Pierre
Published: October 2010

For energy production and also for the glass industry, finding new refractory alloys which could permit to increase the process temperatures to 1200°C or more is a permanent challenge. Chromium base alloys can be good candidates, considering the melting point of Cr itself, and also its low corrosion rate in molten glass. Two families of alloys have been studied for this purpose, Cr-Mo-W and Cr-Ta-X alloys (X= Mo, Si..). A finer selection of compositions has been done, to optimize their chemical and mechanical properties. Kinetics of HT oxidation by air, of corrosion by molten glass and also creep properties of several alloys have been measured up to 1250°C. The results obtained with the best alloys (Cr-Ta base) give positive indications as regards the possibility of their industrial use.
Effects of Firing Conditions on the Coal Ash Fusibility Test
Authors: Montinaro Dario , Malavasi Massimo , Amante Gloria , Chiechi Antonio , Licciulli Antonio
Published: October 2010

In the present work, the melting behaviour of ashes obtained from the combustion of coals from different seams were investigated by a laboratory-scale equipment. The ash melting behaviour was studied by heating the specimens in a tubular furnace under a controlled gas atmosphere, while continuous monitoring the shape transformation by a digital camera. The ash fusibility temperatures (AFT) were determined by using an application which allows the in-line identification of the AFT-related shapes specified in the ASTM D 1857-04.
The effect of the furnace gas-atmosphere on the determination of the ash fusion temperatures were studied by performing the measurements under dry-air, SO2-rich-air and humidified air environments. It was found that under dry conditions, AFT determination is significantly affected by slag foaming, leading to an overestimation of the melting temperatures. Low water vapour concentrations does not appreciably change the results obtained under dry air, while SO2-rich atmosphere seems to reduce foaming. As a result, since no volume expansion was observed, samples heated under SO2-air flow, apparently melt at lower temperatures with respect to dry air conditions. The mineral phases transformation of the ashes during the heating process was studied by X-Ray diffraction and it was found that the low temperature transformations are essentially related to Iron and Alkalis reaction with aluminosilicates to form a glassy phase. On the other hand, high temperatures transformations are related to quartz and mullite solubilization which is closely dependent to the amount of Calcium, and therefore of anorthite phase, in the ash sample.
The Influence of Helium and ODS on the Irradiation-Induced Hardening of Eurofer97 at 300°C
Authors: Heintze Cornelia , Bergner Frank , Kögler Reinhard , Lindau Rainer
Published: October 2010

The influence of helium on the mechanical properties of reduced-activation ferritic/martensitic Cr-steels under fusion-relevant irradiation conditions is still a concern. While the fact that He can influence the mechanical properties is well established [1,2], the underlying mechanisms are not fully understood [1,2]. In this work the effect of He and displacements per atom (dpa) on the irradiation-induced hardening of Eurofer97 at 300°C was studied. Self-ion irradiation was applied to simulate the neutron-irradiation-induced damage. Helium was implanted prior to (pre-implantation), simultaneously (dual-beam irradiation) or following the (post-implantation) self-ion irradiation to investigate the He effect. Nanoindentation was used in order to characterize the damage layer. Under the present conditions (300°C, 1 dpa, 10 appmHe) the observed hardening increased in the following order: single-beam Fe-ion irradiation/pre-implantation < simultaneous implantation < post-implantation. We conclude, that there is a significant interaction between damage and He.
Additionally, Eurofer97 and ODS-Eurofer were irradiated with Fe ions up to 1 and 10 dpa to study the effect of the oxide particles on the irradiation-induced hardening. We have found a higher irradiation-induced hardening at 1 dpa for ODS-Eurofer but a steeper hardness increase per dpa up to 10 dpa for Eurofer97.
Using the Vitrification Test Rig for Process Improvements on the Waste Vitrification Plants
Authors: Short Rick , Gribble Nick , Turner Edward , Riley Andrew D.
Published: October 2010

The Vitrification Test Rig (VTR) is a full scale non-active waste vitrification plant (WVP), that replicates the lines used for immobilising highly active reprocessing waste at Sellafield in the UK. In the high level waste (HLW) vitrification process, liquid HLW is dried in a rotating tube furnace then mixed with an alkali borosilicate glass frit. This mixture is heated to form a homogeneous product glass that is poured, cooled and stored in steel canisters. The primary function of the VTR is to trial and develop methods to increase the efficiency of high level waste processing at the active WVP. Efficiency gains are mainly achieved by increasing the rate at which the immobilised product is created and by increasing the ratio of HLW to glass frit in the product. The VTR has also been used to investigate the chemistry of various process additions and conditions, the effects of potential fault scenarios, and the processing of dilute waste streams that will be received by WVP in the future. All of these areas have the potential to improve processing efficiency through the optimisation of process conditions and the minimisation of unplanned plant outages. This paper discusses several VTR campaigns that have led to overall improvements of WVP operation.
Lessons Learned from the Yucca Mountain and WIPP Projects
Authors: Bonano Evaristo J. , Kessel David S. , Dotson Lori J.
Published: October 2010

For more than 30 years Sandia National Laboratories (SNL) has played a key role in the development and implementation of total system analyses of waste management systems in the United States. Two very important applications have been the total system analysis of long term performance that supported (1) the Compliance Certification Application (CCA) for the Waste Isolation Pilot Plant (WIPP) in 1996 and (2) the License Application (LA) for the Yucca Mountain (YM) Repository in 2008.
Utilization of Hydride Materials in Nuclear Reactors
Authors: Konashi Kenji , Yamawaki Michio
Published: October 2010

Metal hydrides have high hydrogen atom density, which is equivalent to that of liquid water. Fast neutrons are efficiently moderated by hydrogen in metal hydrides. Metal hydrides have been studied for their potential application as nuclear materials in fast reactors (FRs). Two types of the utilizations of metal hydride in FRs are discussed in this paper. One is the utilization for transmutation target of long-lived nuclear wastes. Hydride fuel containing 237Np, 241Am and 243Am has been studied as a candidate transmutation target to reduce the radioactivity of long-lived nuclides included in reprocessed nuclear wastes.

An application of the hafnium hydride has been investigated as neutron absorber in FRs. The core design has been performed to examine its characteristics and to evaluate the cost reduction effect. Demonstration of fabrication of hydride pin has been done with hydride pellets and stainless steel cladding. Coating technique of inner cladding surface has been also developed to reduce the permeation of hydrogen through stainless steel cladding. Physical and chemical properties of the pellet have been measured for designing the hydride pin. The integrity of the pellets at high temperature has been tested and their compatibility with sodium has also been tested. Irradiation test of hydrides has been performed in the fast experimental reactor, JOYO, at Japan Atomic Energy Association (JAEA).
From High to Low Enriched Uranium Fuel in Research Reactors
Authors: van den Berghe Sven , Leenaers Ann , Koonen Edgar , Sannen Leo
Published: October 2010

Since the 1970's, global efforts have been going on to replace the high-enriched (>90% 235U), low-density UAlx research reactor fuel with high-density, low enriched (<20% 235U) replacements. This search is driven by the attempt to reduce the civil use of high-enriched material because of proliferation risks and terrorist threats. American initiatives, such as the Global Threat Reduction Initiative (GTRI) and the Reduced Enrichment for Research and Test Reactors (RERTR) program have triggered the development of reliable low-enriched fuel types for these reactors, which can replace the high enriched ones without loss of performance. Most success has presently been obtained with U3Si2 dispersion fuel, which is currently used in many research reactors in the world. However, efforts to search for a replacement with even higher density, which will also allow the conversion of some high flux research reactors that currently cannot change to U3Si2 (eg. BR2 in Belgium), have continued and are for the moment mainly directed towards the U(Mo) alloy fuel (7-10 w% Mo). This paper provides an overview of the past efforts and presents the current status of the U(Mo) development.
Fabrication of Fuel and Recycling of Minor Actinides in Fast Reactors
Authors: Somers Joseph
Published: October 2010

Fuels for future fast reactors will not only produce energy, but they must also actively contribute to the minimisation of long lived wastes produced by these, and other reactor systems. The fuels must incorporate minor actinides (MA = Np, Am, Cm) for neutron transmutation into short lived isotopes. Within Europe oxide fuels are favoured. Transmutation can be considered in homogeneous or heterogeneous reactor recycle modes (i.e. in fuels or targets, respectively). Fabrication of such fuels can be made by advanced liquid processing methods, enabling property determination and screening irradiation experiments. This paper will describe these fabrication processes, and discuss properties and fuel irradiation experiments made to date. Both fertile and inert matrix fuel types are considered.
Multi-Layered Thermoelectric Power Generator
Authors: Suzuki Ryosuke O.
Published: October 2010

Thermal fluids are served to give the greater ΔT to the thermoelectric (TE) junctions. For the larger power generation using a limited number of modules and the limited amounts of thermal fluids, the multi-layered TE panels can save the occupied space effectively. Because the temperatures of the fluids vary along the planer TE panels due to heat exchange through the panels, the directions of fluids is important to obtain the larger output power, P, from a TE power generator. The methods to stack a few long planer TE panels and to determine the fluid directions are mathematically studied from the steady-state heat exchange. P for various kinds of fluid directions are calculated. P commonly shows the maximum against the panel length because of the balance between the internal resistance and ΔT. This maximum of P can be further maximized by choosing the counter flow. The non-dimensional analysis predicts that two fluids should flow in counterwise. When two series of fluids are used, the circulation method is another key issue for the optimal TE design.
Design Analysis of a-Si/c-Si HIT Solar Cells
Authors: Nawaz Muhammad
Published: October 2010

A theoretical design analysis using numerical two dimensional computer aided design tool (i.e., TCAD) is presented for a-Si/c-Si based heterojunction (HJ) solar cells. A set of optical
beam propagation models, complex refractive index models and defect models for a-Si material
implemented (in-built) in the simulation software are first evaluated for single (SHJ) and double
heterojunction (DHJ) devices. Assessment is further carried out by varying physical parameters of
the layer structures such as doping, thickness of the c-Si and a-Si layers, defect density in the a-Si
layer and bandgap discontinuity parameter. With varying bandgap discontinuity and using standard
transport model in numerical device simulation, HJ solar cell performance is undervalued (η =
19.5%). This is the result of poor photogenerated carrier collection due to the presence of
heterojunction at the respective n and p-contacts of the device. Implementing thermionic field
emission tunneling model at the heterojunction, we obtained improved performance (η = 24 %) over
large range of bandgap discontinuities. Keeping improved efficiency of HJ cell, implementing a step
graded a-Si layer, further helps to widen the range of bandgap discontinuity parameter.