L0013 – Thermal expansion properties of some sealing and related glasses and glass ceramics
L0002 – Phase equilibrium and martensitic transformation in lanthana doped zirconia
The system ZrO2-La2O3 has been studied in the 0 to 15 mol% La2O3 range using X-ray diffraction and thermal analysis. Two kinds of diagrams were elaborated: First is a phase equilibrium diagram where the eutectoid decomposition of ZrO2,ss(T) => ZrO2,ss(M) + Pyss occurs at 1100°C and 0.75 mol% La2O3 (Py is the pyrochlore compound Zr2La2O7). The maximum solubility of La2O3 in ZrO2,ss(M) is 0.5 mol% at room temperature. Second, a nonequilibrium diagram is determined showing the correlations between grain size, La2O3 content, and the martensitic transformation temperature start (Ms).
L0023 – Colloidal processing and sintering of nanosized transition aluminas
The dispersion of nanosized gamma aluminas with high specific surfaces areas (100 m2/g) and primary particle sizes around 20 nm, using
polyacrylic acid, has been investigated. The effect of pH and polymer concentration showed that the highest density green bodies were
produced using high polymer concentrations (6 wt.%) and pH of 6. Interparticle potential calculations have been made and help explain the
underlying dispersion mechanism at least on a qualitative level. The dispersions were then used to slip cast green bodies followed by drying
and sintering. The types of gamma alumina powder have been investigated, the pure gamma alumina, doped with MgO and also with the
addition of alpha alumina seeds. The high degree of agglomeration of the gamma alumina powders led to very low densities (60%) even the
alpha seeded alumina reached only 85% theoretical density. Attrition milling with zirconia media improves both green density and sintered
densities significantly with all powders showing sintered densities >97%. Microstructural analysis on polished and etched surfaces show,
however, that the grain sizes are well above 1 Am over 50 times greater than the initial gamma alumina primary particles. A two-step sintering
cycle was investigated with the Mg doped powder and average grain sizes around 580 nm were achieved.
L0012 – Sintering of a transition alumina : Effects of phase transformation, powder characteristics and thermal cycle.
The effects of several parameters on the pressureless sintering of a commercially available transition alumina has been investigated. The capacity of the particles to re-arrange during the phase transformation into the alpha-alumina phase has been shown to be a key feature in the densification mechanism. The degree to which the particle re-arrangement can lead to an enhanced densification over and above the change in density due to the phase transformation from y to alpha phase depends on several parameters: compact density, heating rate and the amount of alpha-alumina present in the as-supplied raw powder. The parameters influencing the degree of particle re-arrangement and what directions to take to improve on the above densities and grain sizes are discussed.
L0001 – Sintering behaviour of Y(u)Ba(v)Cu(w)O(7-d) (u ? 1; v ? 2; w ? 3)
L0022 – Evolution of the coefficient of thermal expansion of a thermosetting polymer during cure reaction
The evolution of the coefficient of thermal expansion (CTE) of a thermosetting polymer during cure reaction is an important parameter for
industrial applications such as composite processing since it influences the development of internal stresses in the material. The CTE being
almost impossible to measure on a reacting thermoset, we propose to use an indirect method based on the modelling of ionic conductivity by
a modified WLF equation, allowing to calculate the evolution of CTE from dielectric spectroscopy measurements. This method is applied to
a dicyanate ester thermosetting polymer, leading to encouraging results both qualitatively and quantitatively.
L0011 – Pre-eutectic densification of calcium carbonate doped with lithium carbonate.
Pressureless sintering of CaCO3 was carried out, with Li2CO3 (from 0.5 to 8 wt%) as an additive, under different pressures of CO2. Densification occurs between 600 and 700°C. Sintering above the eutectic temperature (T>662°C) leads to the decomposition of calcium carbonate and the materials become expanded. At 620° under 1 kPa of CO2, a relative density of 96% is reached. Li2CO3 enhances the densification process and grain growth of calcium carbonate. CO2 pressure slows down densification and grain growth kinetics. These results are explained by the influence of carbonate and calcium ion vacancies on the sintering mechanisms.
HE0086 – Volumetric hydrogen sorption measurements e Uncertainty error analysis and the importance of thermal equilibration time
The design of a volumetric measurement apparatus is studied by means of an uncertainty analysis to provide guidelines for optimum hydrogen sorption measurements. The reservoir volume should be as small as possible (i.e., 10 cc) to minimize the uncertainty. In addition, the sample mass loading has a profound effect on the uncertainty and the optimum loading is a function of the sample's intrinsic storage capacity. In general, the higher the sample mass loading the lower the uncertainty, regardless of any other parameter. In cases where the material to be tested is not available in gram quantities, the use of high accuracy pressure and temperature transducers significantly mitigates the uncertainty in the sample's hydrogen uptake. Above all, the thermal equilibration time is an important parameter for high accuracy measurements and needs to be taken into consideration at the start of the measurements. Based on a computational analysis, a 5 min wait time is required for achieving thermal equilibrium when the instrument enclosure temperature is different than the ambient temperature.
L0021 – Mullite compacts obtained by colloidal filtration of alumina powders dispersed in colloidal silica suspensions
This work deals with the manufacture of mullite-matrix composites by a colloidal filtration route. Avariation of the transient viscous sintering process is studied in which submicrometer sized alumina particles are dispersed in a nanosize colloidal silica
L0010 – Dimensional stability and defect chemistry of doped lanthanum chromites.
Acceptor doped lanthanum chromites are potential interconnect materials to be used in high temperature Solid Oxide Fuel Cells (SOFC). However, instability of these materials when exposed to low oxygen partial pressure causes a volume expansion that can be detrimental to the SOFC performance. The stability of La0.8Sr0.2Cr0.97V0.03O3 is determined as function ofpO2 and temperature by isothermal thermogravimetry and dilatometry. The experimental data are analysed using a simple model for the defect chemistry. The relation between expansion behaviour and change in defect chemistry is discussed using a simple structural model.
HE0085 – Reversible hydrogen storage in the Li-Mg-N-H system. The effects of Ru doped single walled carbon nanotubes on NH3 emission and kinetics
In this study, the LiNH2?MgH2 (2:1.1) complex hydride system (Li?Mg?N?H is investigated in terms of hydrogen ab/desorption kinetics and the concomitant NH3 emission levels. By selecting more intense ball milling parameters, the hydrogen ab/desorption kinetics were improved and the NH3 emission reduced. However, it is shown that NH3 emission cannot be completely eliminated during ball milling. Single walled carbon nanotubes (SWCNTs) and 20 wt.% Ru doped SWCNTs are utilized as catalysts to study their effects on NH3 emission and kinetics characteristics of the Li?Mg?N?H system. The SWCNT doped sample did not show any kinetics improvement, whereas the SWCNT-20Ru doped sample showed similar kinetics performance as that of the base sample. More importantly, the presence of SWCNT increased the NH3 emission as compared to the base sample. On the other hand, SWCNT-20Ru doping reduced the NH3 emission compared to the SWCNT doping, but did not eliminate it completely. As revealed from the mass spectrometry signals, the SWCNT-20Ru catalyst starts to decompose NH3 at a temperature as low as 200 °C.
L0020 – Synthesis and sintering of porous La0.8 Sr0.2 MnO3 powder
In this research, La0.8Sr0.2MnO3 precursors were synthesized from metallic nitrates by sol-gel method using polyacrylic acid (PAA) as the chelating to prepare pure and porous powders for the cathode application in solid oxide fuel cell (SOFC). The LSM powders after dried and sintered at suitable temperatures were characterized by X-ray diffractometry (XRD), scanning, and transmission electron microscopes (SEM and TEM). The LSM powder with nano-crystalline synthesized by adding (P)AA/LSM = 2 was obtained after calcined at 500°C for 2h, and still kept porous character up to 1000°C.
L0009 – Microstructure and piezoelectric properties of slip cast barium titanate ceramics
HE0084 – Remarkable irreversible and reversible dehydrogenation of LiBH4 by doping with nanosized cobalt metalloid compounds
Nanosized cobalt sulfide and cobalt boride were synthesized and doped into LiBH4 to improve the dehydrogenation properties of this important candidate for hydrogen storage. With respect to CoSx doping, the dehydrogenation temperature (peak temperature observed by mass spectrometry) of pristine LiBH4 can be reduced from 440 °C to 175 °C with a maximum capacity of 6.7 wt% at 50% doping. Unfortunately, B2H6 is liberated and the process is not reversible because the CoSx dopant reacts with LiBH4 to form more stable compounds. By changing CoSx to CoBx, a reversible dehydrogenation was realized with greatly improved reversibility. The dehydrogenation temperature was reduced to 350 °C with a maximum capacity of 8.4 wt% at 50% doping amount. It is very significant that CoBx is stable and the release of B2H6 is eliminated. A reversible hydrogen desorption of about 5.3 wt% can be achieved with a LiBH4 + 50% CoBx mixture under a mild rehydrogenation condition of 400 °C at 10 MPa H2. It is obvious that CoSx acts as a reactant even though the dehydrogenation is greatly enhanced, while CoBx behaves as a catalyst significantly promoting the dehydrogenation and reversibility of LiBH4.
L0019 – Processing and characterization of La2O3/Al2O3/B2O3 based glass-ceramics for LTCC application
A lead-free, non-alkali and low-sintering temperature, La2O3-Al2O3-B2O3 (LAB) glass with Al2O3 filler had been investigated for LTCC application. The glass melting, processing window of tape casting, and sintering of the LAB glass-ceramic systems the wetting behaviors of the LAB glass on alumina plate, and the crystallization kinetics in the LAB/Al2O3 glass-ceramics were also studied. Moreover, systematic studies of thermal characteristics, phase transformation and microstructures during different heat-treatments were investigated by DTA, XRD, TMA, SEM/EDS, TEM, and AEM. The densification and crystallization temperatures of LAB glass performed between 800°C-850°C. Additionally, the sintering and dielectric properties of layer LAB/Al2O3 glass-ceramics with Ag electrode were also measured. The densification kinetics and possible defects during the cofiring will be reported.
L0008 – Effect of Yttrium doping on sintering of fine grained alumina
HE0083 – Muon spin relaxation reveals the hydrogen storage mechanism in light alkali metal fullerides
We report a muon spin relaxation investigation of Li6C60 and Na10C60 fullerides, which have been recently demonstrated to be efficient and reversible H2 absorbers above 570 K. We prove that, differently from other fullerides, a sizeable fraction of implanted muons form C60 muonium adduct radicals, with hyperfine coupling depending on the C60 hydrogen coverage. Surprisingly, the fraction of radicals was found to increase up to 65% when lowering T to 5 K in Na10C60Hy. This indicates that hydrogen interaction in these systems is enhanced even at cryogenic temperatures, while the high T needed for hydrogen absorption is only required to overcome the H2 dissociation barrier mediated by alkali metals.
L0018 – The linear thermal expansion and the thermal diffusivity measurements for near-stoichiometric (U, Ce)O2 solid solutions
The thermal diffusivities of near-stoichiometric (U, Ce)O2 solid solutions containing CeO2 up to 22 mol% were investigated in the temperature range of 298-1273 K using the laser flash method. Also, linear thermal expansion measurements were performed in the temperature range of 298-1673 K using a thermomechanical analysis. The thermal conductivities were determined by a calculation of the thermal diffusivity, the density and the specific heat. The thermal conductivities of the tested samples could be expressed as a function of the temperature by the phonon conduction equation k = (A + BT)-1. The thermal conductivity decreased gradually with an increasing Ce content. This was attributable to the increasing lattice defect thermal resistance caused by the U4+, Ce4+ and O2- ions as phonon scattering centers.
L0039 – Low sintering temperature of MgTiO3 for type I capacitors
Magnesium titanate MgTiO3 is a well-known compound for type I multilayer ceramic capacitors. Nevertheless, the sintering temperature of
the pure ilmenite MgTiO3 is around 1350°C. Such a high sintering temperature together with the high sensitivity of the dielectric material to
reduction when heated in a low-oxygen containing atmosphere implies that MgTiO3-based MLCC include palladium-rich inner electrodes.
The high level of variation of both the costs of Pd and Ag justifies research leading to the use of cheaper metals such as silver or base metals
such as nickel or copper. When using low-melting temperature metals (silver melts at 960°C and copper at 1085°C), the sintering temperature
of the dielectric material has to be lowered.We report here on our investigations into the use of fluorine containing additives for the reducing of
the sintering temperature of magnesium titanate, showing the ability of this material to be sintered at temperatures much lower than 1000°C.
Both dielectric and electric properties of such ceramics are compatible with type I capacitors requirements.
L0028 – Synthesis and characterisation of the double perovskite Ba2(Zn0.5Ti0.5X)O6 (X = Nb, Ta) ceramics
Ba2(Zn0.5Ti0.5X)O6 compounds from the general ABO3 perovskite family were synthesized by the classical
solid-state route for X = Nb and Ta with various A/B ratios (1.005, 1 and 0.995). After the calcination step at
1100°C, both compounds (X = Nb and Ta) contain mainly the cubic disordered 'Ba2(Zn0.5Ti0.5X)O6' phase but
traces of BaTiO3 and secondary phases are often detectable. Nevertheless, after the sintering stage at higher
temperature (from 1300 to 1500°C) and for all A/B ratios investigated, Ti enters into the cubic perovskite structure,
resulting in the formation of a unique 'Ba2(Zn0.5Ti0.5X)O6' phase. Attractive dielectric properties have been
measured on the tantalum-based compound for A/B = 0.995 (Q 2000 at 7.4 GHz and e = 39.6) as well as on the
niobium-based phase for A/B = 1.005 (Q 2200 at 6.1 GHz and e = 54.8). All these characteristics were confirmed
at 1 MHz and a linear dependence of the permittivity versus temperature from 60 to 180°C has also been
evidenced for both formulations. Sinterability, dielectric properties and microstructure of such compounds are
discussed with respect to the stoichiometry.
L0049 – Titanium effect on phase transformation and sintering behavior of transition alumina
The sintering behavior of doped gamma-alumina powders studied by dilatometry and electron microscopy is analysed with a particular emphasis
on the role of titanium on the various densification steps. Compared with other doping elements, such as Mg, Y and Zr, which do not improve
alpha-phase densification, titanium enhances this densification step by a fast decrease of internal colony porosity. This internal densification of
single crystalline zones is attributed to the lengthening of the elementary bricks in titanium-doped samples.Atransient increase in densification
rate is also observed, corresponding to the precipitation when during grain growth, grain boundaries become saturated with titanium. Final
densities close to the theoretical values are obtained.
L0038 – High decrease in CaZrO3 sintering temperature using complex fluoride fluxes
The effects of complex fluoride flux on the sintering and the electric/dielectric properties of CaZrO3 ceramics are investigated. Four fluoride
mixtures are tested: LiF-CaF2-SrF2, LiF-CaF2-BaF2, LiF-SrF2-BaF2 and LiF-BaF2-B2O3. They are used because each of their associated
phase diagrams shows the existence of an eutectic composition having a low melting temperature. This liquid phase is used to promote
the densification at low temperature. The effect of various additions (nature and quantity) are also investigated to optimise the resulting
thermal and physical properties. In terms of sintering behaviour, the results are unambiguous, leading to a drastic decrease of the densification
temperature with all the non-boric additions (<1000°C). The dc/ac measurements carried out on the materials sintered at low temperature
(900 and 1000°C) and either in air or in reductive atmosphere follow the same trend when using non-boric additions, with high permittivities
(>25), low dielectric losses (<10x10^(-4)), low temperature coefficients of the permittivity (<100 ppm/K) and high insulating resistivities (up
to 10^15 ohm.cm); the high frequency measurements lead to similar conclusions revealing high QF products (up to 40 THz) using non-boric
additions. The effect of the sintering temperature, the sintering atmosphere, the flux composition and its amount on these properties are also
L0027 – Influence of titanium nitride addition on the microstructure and mechanical properties of TiC-based cermets
In this paper, the TiC-based cermets with addition of TiN were fabricated by a conventional powder metallurgy process. The
titanium nitride (TiN) and titanium carbide (TiC) used as starting powders have been synthesized by the self-propagating high temperature
synthesis (SHS) method. This exothermic reaction, easy to process, allows to obtain fine and original powders from lowcost
raw materials. Cermets obtained by sintering powders of TiC and Mo2C with nickel binder phase are investigated. The effect of
TiN adding on the microstructure and the mechanical properties of these composites are studied. Microstructures have been
observed by scanning electron microscopy (SEM). Room temperature mechanical properties such as Young s modulus, fracture
toughness and microhardness have been measured and related to morphology and chemical composition of the samples. Tribological
experiments were also performed and the friction coefficient of a cermet containing titanium nitride was compared with that of
other hard materials. The SHS starting powders used present some particularities, as it was shown in a previous study [Mate´riaux a`
base de carbures et nitrures, pour coupe et usure, obtenus a` partir de poudre SHS, PhD Thesis, INSA Lyon, 2004]. The purpose of
this work is to show that results concerning the impact of TiN addition on microstructure and mechanical properties obtained on
bulk specimens, from these original starting powders, are similar to the ones obtained on alloys from commercial starting powders.
L0048 – Effect of type of primary processing on the microstructure, CTE and mechanical properties of magnesium/alumina nanocomposites
Magnesium based composites containing 2.5wt.% of nano-sized Al2O3 (50nm) particulates reinforcement were synthesized
using an innovative disintegrated melt deposition technique and blend-press-sinter powder metallurgy technique followed by
hot extrusion. Microstructural characterization of the materials revealed uniform distribution of reinforcement, grain refinement
and the presence of minimal porosity. Properties characterization revealed that the presence of nano-Al2O3 particulates led to
an increase in dimensional stability, hardness, elastic modulus, 0.2% yield strength, UTS and ductility of pure magnesium.
Amongst the composites, the ingot metallurgy processed material exhibited superior modulus and ductility while powder metallurgy
processed material exhibited superior yield strength and ultimate tensile strength. The results further revealed that the overall
combination of tensile properties of these materials remained superior when compared to high strength magnesium alloy AZ91
reinforced with much higher weight percentage of SiC. Fractography studies revealed that the typical brittle fracture of pure magnesium
changed to ductile due to the incorporation of nano-Al2O3 particulates. An attempt is made in the present study to correlate
the effect of nano-sized Al2O3 particulates as reinforcement and processing type with the microstructural and tensile
properties of magnesium.
L0037 – Low temperature sintering of the binary complex perovskite oxides xBa(Zn1/3Ta2/3)O3 + (1-x)Ba(Mg1/3Ta2/3)O3
The interest for the complex perovskites oxides is known since several years. Ba(Zn1/3Ta2/3)O3 (BZT) and Ba(Mg1/3Ta2/3)O3 (BMT) have been
broadly studied due to their attractive dielectric properties suitable for applications such as multilayer ceramic capacitors or hyperfrequency
resonators. They hence exhibit at 1MHz very low dielectric losses combined with a high relative dielectric constant which is stable with
the temperature. Unfortunately, these materials needs a too high temperature to reach a satisfying density. The BMT sintering temperature
is indeed higher than 1500°C, which is too high to envisage a co-sintering with copper (Tf = 1083°C) or nickel (Tf = 1450°C). To lower the
sintering temperature, a glass phase addition is performed on the complex formulations xBa(Zn1/3Ta2/3)O3 + (1-x)Ba(Mg1/3Ta2/3)O3 (with
x = 0, 1/3, 1/2, 2/3 and 1). These mixtures are envisaged to explore their dielectric properties. The sintering temperature lowering reached is
higher than 400°C when 10 molar% of borate oxide is added to the mixtures and their dielectric properties are very attractive (? = 25 and
?? =-59 ppm/°C for x = 1/3) for the fabrication of base metal electrodes multi layer ceramic capacitors (BME-MLCC).
L0047 – Variation of the lattice parameter and thermal expansion coefficient of (U,Dy)O2 as a function of DyO1.5 content
Thermal expansions of (U,Dy)O2 solid solutions were investigated between room temperature and 1673K by using a thermo-mechanical
analyzer. The lattice parameter of (U,Dy)O2 pellets is lower than that of UO2 and it decreases as Dy content increases. The linear thermal
expansion and average thermal expansion coefficients of (U,Dy)O2 are higher than that of UO2. For the temperature range from room
temperature to 1673 K, the average thermal expansion coefficient values for UO2 and (U0.8Dy0.2)O2 are 10.97x10^(-6) and 11.37x10^(-6) K-1,
L0036 – Dielectric properties of Ba(Mg,Zn)1/3Nb2/3O3 and effect of B2O3 and LiF addition
The dielectric and microwave properties of (x)BaZn1/3Nb2/3O3-(1-x)BaMg1/3Nb2/3O3 (BMZN) mixture were investigated. The complex
perovskite-type ceramics Ba(Zn1/3Nb2/3)O3 (BZN) and Ba(Mg1/3Nb2/3)O3 (BMN) have a high dielectric constant (?r = 39 and 33, respectively),
but while BZN has a relative low firing temperature (?1350°C), BMN has a too high sintering temperature (>1500°C) to make it attractive in
some technological applications. Mixing these two dielectric ceramics in different proportions and adding some sintering agents (like glassy
B2O3 and LiF) the sintering temperature can be decreased, and XRD patterns indicates the formation of a solid solution for all x values
investigated. The dielectric properties are preserved or even improved for some specific combinations. For BMZN (x = 1/4), without any
dopants, the Qf factor is 76.7 THz for f = 7.6 GHz and the temperature coefficient of the resonant frequency tf is -4 ppm/°C, which is the best
value for BMZN. These values make BMZN compounds suitable for microwave resonator applications.
We highlight in this paper that BMZN materials can be successfully sintered at low temperature (i.e. 940°C), opening opportunities to
manufacture base metal electrodes multilayer ceramic capacitors (BME-MLCC).
L0046 – Elaboration and characterisation of apatite based mineral supports for microfiltration and ultrafiltration membranes
The development and the characterisation of new supports for microfiltration and ultrafiltration membranes from apatite applied to filtration are
presented. The choice of this material is based primarily on its low cost (considering its abundance in the Tunisian ores).
The support, with tubular configuration, was prepared from natural apatite: apatite powders were crushed for 30 min and sieved to 200 mm. The
resulting powders, mixed with organic additives and water, could be extruded to elaborate a porous structure. The firing temperature of the support
is 1160°C. The morphologies of the surface and the cross-section observed on scanning electron microscope (SEM) are homogeneous and do not
present any macro defects (cracks, etc.). The mean pore diameter, measured by mercury porosimetry, is 6 mm and the pore volume is 48%.
L0035 – Dielectric and electromechanical characterisation of fine-grain BaTi0.95Sn0.05O3 ceramics sintered from glycolate-precursor powder
Nanocrystalline BaTi0.95Sn0.05O3 (BTS-5) powder was synthesised from glycolate-precursors, and used to sinter fine-grain BTS-5 ceramics.
We compare sintering behaviour, microstructure as well as dielectric and electromechanical properties of the advanced ceramics with ceramics
sintered from classical mixed oxide powder.
L0045 – Electrical and microstructural characterization of spinel phases as potential coatings for SOFC metallic interconnects
Several spinel samples, i.e., MnxCr3-xO4 (0.5
L0034 – Electrical, thermal and catalytic properties of CeO2-Sm0.5Ti0.5O1.75 ceramics
The electrical conductivity of the ceramic composite, (CeO2)(1-x)(Sm0.5Ti0.5O1.75)x, where 0
L0044 – Enhancing strength and ductility of Mg/SiC composites using recrystallization heat treatment
In the present study, magnesium composites with sub-micron size silicon carbide (SiC) particulate reinforcements were
successfully synthesized using an innovative Disintegrated Melt Deposition technique followed by hot extrusion. The extruded
materials were characterized for their microstructural, thermal and mechanical properties. Systematic investigations on
the microstructure of the extruded samples revealed a fairly uniform distribution of SiC particulates with limited clustering.
Good SiC/Mg interfacial integrity and limited porosity was observed for all the samples. The results of the properties
characterization revealed that SiC in sub-micron length scale are more effective in lowering CTE, and enhancing hardness,
0.2% yield strength, and ultimate tensile strength when compared to SiC particulates in micron length scale. Subsequently,
isothermal heat treatment at 150°C for 5 h was carried out for the composite samples. The results of tensile testing
revealed that the heat treated samples showed an improvement of 0.2% YS, UTS and ductility. Particular emphasis is placed
in this study to investigate the effect of heat treatment at the recrystallization temperature on the tensile properties of
L0033 – Sintering, microstructure and grain growth of Fe-doped Ce0.9Gd0.1O2 d ceramics derived from oxalate coprecipitation
The precursor powder of Ce0.9Gd0.1O2 d ceramics was prepared by oxalate coprecipitation. 0.1-3 at% (atomic
percent) Fe2O3 was added into the powder via the conventional mixed-oxide method. The effects of doping level, and
sintering temperature and time on the densification, microstructure and grain growth of Ce0.9Gd0.1O2 d ceramics were
investigated by means of dilatometry measurement, density testing and scanning electronic microscopy (SEM)
observation. In the Fe content range used, the sintering temperature decreased consistently with increasing Fe level
(from 1310°C at 0.1 at% Fe to 1104°C at 3 at% Fe). Small additions of Fe2O3 promoted the densification rate
significantly. The densification rate reached a maximum at 1 at% Fe, then decreased with further increase in Fe
content. For 0.5 at% Fe-doped Ce0.9Gd0.1O2 d ceramic, over 97% relative density was complete during heating ramp
fromroomtem perature to 1350°C at a heating rate of 10°C/min, as compared to only 86% for the undoped ceramic.
The Fe doping level was also found to have a remarkable influence on the grain growth behavior, which depended on
sintering temperature. At lower temperatures (e.g., 1250°C), a pinning effect on grain growth was found above 1 at%
Fe additions. However, such a pinning effect became less important with increasing temperature. A slight increase in
grain size was actually observed in the Fe-doped ceramic sintered at 1500°C as the Fe content increased from0.1 to
3 at%. The analysis based on the grain growth kinetics indicated that the undoped Ce0.9Gd0.1O2 d ceramic followed a
parabolic law for grain growth, while the 0.5 at% Fe-doped ceramic had a grain growth exponent of 4.
L0054 – Electrical and thermal properties of La0.7Sr0.3Ga0.6Fe0.4O3 ceramics
Single-phase La0.7Sr0.3Ga0.6Fe0.4O3 (LSGF) ceramic powder was prepared in one step at 1500°C by solid-state reaction in air. The phase
is a hexagonal (space group R-3c) at room temperature but becomes cubic at temperatures above 600°C. A high-density (97%) LSGF
ceramic shows electrical conductivity of 4.3 S/cm (Ea = 0.32 eV) at 600°C in air. The thermal expansion coefficient of LSGF changes
drastically in air due to oxygen loss and phase transition. High-density LSGF ceramic is relatively stable in forming gas (8% H2, 92% Ar).
However, the powder decomposes in forming gas above 700°C with formation of LaSrGaO4. LSGF reacts with NiO at 1000°C. The ability of
LSGF to split the C-H bond in methane at intermediate temperatures has been also evaluated.
L0043 – Stress relaxation of bulk and ribbon glassy Pd40Cu30Ni10P20
Detailed measurements of linear heating and isothermal stress relaxation of bulk and ribbon glassy Pd40Cu30Ni10P20 below the glass
transition temperature have been performed. Using the activation energy spectrum reconstructed from these measurements, the temperature
dependence of the shear viscosity has been calculated. It has been found that this dependence agrees with that derived directly from
the creep measurements. This provides strong support for understanding the stress relaxation as a result of the stress-oriented irreversible
structural relaxation with distributed activation energies.
L0032 – Thermal analysis of the cyclic reduction and oxidation behaviour of SOFC anodes
The reduction and oxidation (redox) kinetics of a Ni/YSZ cermet were studied at temperatures between 400 and 850°C by
thermogravimetric analysis (TGA) and reduction and oxidation activation energies were determined. In addition, the volume change after
redox cycling was examined by thermomechanical analysis (TMA). Samples with fine microstructure similar to a typical SOFC anode
functional layer (AFL) and samples with coarse microstructure similar to a typical anode substrate were characterized.
Coarse structured samples experienced no volume change or cracking upon redox cycling. Fine structured anode samples did not
change in volume after reduction, but expanded between 0.9% and 2.5% after oxidation. The samples were significantly cracked after
oxidation. The amount of expansion and cracking was reduced by lowering the Ni content of the anode and by reducing the oxidation
The reduction of the NiO/YSZ samples followed linear kinetics with an activation energy of 78 kJ/mol. Ni/YSZ oxidation followed
parabolic kinetics at temperatures lower than 700°C. A divergence from parabolic kinetics was seen at higher temperatures (700-850°C).
This divergence has been seen in many other kinetic studies and is usually attributed to short-circuit diffusion mechanisms. An activation
energy of 87 kJ/mol was calculated for oxidation.
L0053 – Processing of Al2O3/Y-TZP laminates from water-based cast tapes
Laminated structures have been investigated due to their capability for the reinforcement of ceramics. Crack deflexion and bifurcation, surface
strengthening and threshold strength are the mechanisms associated to the fracture of laminated ceramic. In all the cases, a precise control of the
thickness and composition of the layers is necessary. In this sense, colloidal processing techniques have proved their adequacy for the fabrication
of designed layered structures. This paper deals with the fabrication of layered ceramics by stacking water-based cast tapes at room temperature
and using low pressures. In order to control the pressing procedure, the engineering strain-stress curves recorded during the stacking of the tapes
were analyzed. Afterwards, the sintering conditions have been optimized by adjusting the green density of the tapes to avoid differential sintering
and the associated cracks. Monolithic and layered materials free of cracks have been fabricated using optimized processing conditions.
L0042 – Cofiring behavior and interfacial structure of NiCuZn ferrite/PMN ferroelectrics composites for multilayer LC filters
The cofiring behavior, interfacial structure and cofiring migration between NiCuZn ferrite and lead magnesium niobate (PMN)-based relaxor
ferroelectric materials were investigated via thermomechanical analyzer (TMA), X-ray diffractometer (XRD), scanning electron microscopy
(SEM) and energy dispersive X-ray spectroscopy (EDS). Mismatched sintering shrinkage between NiCuZn ferrite and PMN was modified
by adding an appropriate amount of sintering aids, Bi2O3, into NiCuZn ferrite. Pyrochlore phase appeared in the mixture of NiCuZn ferrite
and PMN, which is detrimental to the final electric properties of LC filters. EDS results indicated that the interdiffusion at the heterogeneous
interfaces in the composites, such as Fe, Pb, Zn, existed which can strengthen combinations between ferrite layers and ferroelectrics layers.
L0031 – A study of Pr0.7Sr0.3Fe(1-x)NixO(3-d) as a cathode material for SOFCs with intermediate operating temperature
Pr0.7Sr0.3Fe(1-x)NixO(3-d) (PSFN; x=0.2-0.5) compounds were synthesized and characterized by powder X-ray diffraction (XRD),
thermal expansion coefficient (TEC) measurements, electrical conductivity and electrochemical impedance spectroscopy on coneshaped
electrodes on a Ce0.9Gd0.1O1.95 (CGO10) electrolyte. The main phase of the powders belongs to the orthorhombic crystal
system. The conductivities are fairly high, e.g., around 450 S.cm-1 at 600°C for the x=0.3 compound. The TEC of the
compounds is close to the values of ceria-based electrolytes. PSFN showed hysteresis in the temperature dependence of the
conductivity, TEC and area-specific polarization resistance Rpol. It is considered that the hysteresis was caused by relatively slow
adjustment of the oxygen stoichiometry. The electrochemical performance Rpol 1 of the PSFN compounds is similar to that of
L0052 – Effect of ceria on properties of yttrium-doped strontium titanate ceramics
This work reports the preparation and properties of the ceramic mixtures of the A-site deficient perovskite Sr0.94Y0.04TiO3 (SYT) with
CeO2 in a range of ratios with a view to establishing their potential as anode materials for solid oxide fuel cells. Good electrical conductivity
that decreased with increasing CeO2 content was observed on reduction in forming gas. The composition with 50 wt.% of CeO2 showed the
conductivity of 7.0 S/cm at 900°C in forming gas. The thermal expansion of SYT-CeO2 ceramics in forming gas and in air were investigated
in the range 25-900°C at a ramping rate of 3°C/min and thermal expansion coefficients were determined. The addition of ceria was found to
have a positive influence on the catalytic behavior of SYT-CeO2 ceramics towards steam methane reforming.
L0041 – Surface resistance and sensitivity to hygrometry of various ceramic compositions for multilayer capacitors
Developing new dielectric compositions for multilayer ceramic capacitors, the authors of this work have observed an influence of hygrometry
on the insulation resistance behavior of some of them. The swiftness of the phenomenon let us suppose a surface mechanism. Prompted
by these observations, we have investigated the sensitivity of various conventional ceramic compositions to hygrometry by measuring their
surface resistance versus the moisture rate in air. The studied materials are formulations for type I and type II ceramic capacitors. In order
to understand some breakdown phenomena in ceramic multilayer capacitors, we have also investigated the influence of the screen printed
L0030 – Ionic conductivities and phase transitions of lanthanide rare-earth substituted La2Mo2O9
The ion conductivities and phase transitions of lanthanum molybdate (La2Mo2O9) substituted with lanthanide rare-earths are investigated
using impedance spectroscopy, dilatometry, and X-ray powder diffraction. Among the substituted La2Mo2O9 of 10 mol% Ce, Nd, Sm, Gd, Dy,
Er, Yb, the specimens containing Er, and Dy exhibit depressed alpha-beta phase transformation and high conductivities. Their 700°C conductivities
are approximately five to seven times that of La2Mo2O9, around 0.26 S cm-1, comparable with those of (LaSr)(GaMg)O3 and Gd-substituted
CeO2. Among the three compositions of 10 mol% Gd, Dy, Er showing depressed phase transition, Er- and Dy-substituted La2Mo2O9 possess
relatively low thermal expansion coefficient 11 x 10^(-6) K-1, compared with that of the Gd-substituted La2Mo2O9, 18 x 10^(-6) K-1, which
is near that of La2Mo2O9. Hence, Dy and Er are valuable dopants in improving the La2Mo2O9 properties. Across the lanthanide series,
10 mol%-substituted La2Mo2O9 demonstrates systematic variations in the conductivity-temperature relation. Hysteresis phenomena in both
of conductivity and thermal expansion are also observed in those compositions which display phase transition.
L0051 – Sintering and microstructure of rare earth phosphate ceramics REPO4 with RE = La, Ce or Y
Sintering of rare earth phosphates REPO4 (RE = La, Ce or Y) was studied using dilatometry. The presence of a secondary rare earth
metaphosphate phase RE(PO3)3 as sintering aid was investigated. It proved to accelerate the densification but it activated fast grain growth,
which was very detrimental to the microstructural design of processed ceramics. A temperature of 1400-1450°C was required to sinter pure
LaPO4 and CePO4 ceramics with fine grains. Both compounds behave similar while YPO4 did not densify even at 1500°C. The influence of
specific surface area of starting powders, temperature and holding time on the sintering rate and microstructures of dense REPO4 materials is
L0040 – Low temperature sintering of MgTiO3 with bismuth oxide based additions
MgTiO3 is a classical material for type I MLCC. However, its densification temperature is too high to allowco-sintering with copper electrodes.
Investigations into low temperature sintering of MgTiO3 show the complexity of this problem particularly when co-sintering with copper
electrodes and thus a reducing atmosphere are involved in the process. Though feasibility of MgTiO3/copper MLCC seem to be possible
[Bernard, J., Houivet, D., El Fallah, J. and Haussonne, J. M., MgTiO3 for base metal multilayer ceramic capacitors. J. Eur. Ceram. Soc., 2004,
24, 1877-1881] studies have pointed out several remaining problems such as sensibility to hygrometry [Bernard, J., Houivet, D., El Fallah,
J. and Haussonne, J. M., Effect of hygrometry on dielectric materials. J. Eur. Ceram. Soc., 2004, 24, 1509-1511]. Investigations into low
temperature sintering of MgTiO3 are thus still necessary to find a formulation which is not detrimental to dielectric behaviour. Sintering aid
capabilities and/or good dielectric properties of bismuth oxide based additives make them good candidate materials to lower MgTiO3 sintering
temperature without altering its final properties. In this study bismuth titanate is either formed in situ by reaction-sintering of Bi2O3-B2O3
additives with MgTiO3 or obtained by pre-calcination of Bi2O3 and TiO2 powders and then added to MgTiO3 prior to sintering. Bismuth
titanate appears as a good sintering aid that allows sintering of MgTiO3 under 1000°C. It is however highly sensitive to the nature of the
sintering atmosphere, oxidizing or reducing. Dielectric properties of sintered specimens are compatible with type I capacitors applications.
L0029 – Sintering shrinkage of WC-Co materials with bimodal grain size distributions
Sintering shrinkage and densification rate were investigated for WC-Co materials with different grain size distributions. Unimodal
distributions were compared to bimodal mixtures with size ratio close to four. A bimodal carbide mixture with 25% fine
particles showed similar shrinkage behaviour to a material with unimodal distribution around the same mean value. With 50%
fine particles the initial shrinkage was slightly faster than a unimodal material with the same mean size, while the late shrinkage
was considerably slower. The effects of particle size distribution on particle packing and sintering are discussed, and the effect on
L0050 – Ba(Zn1/3Nb2/3)O3 sintering temperature lowering for silver co-sintering applications
The complex perovskite oxide Ba(Zn1/3Nb2/3)O3 have been broadly studied due to its attractive dielectric properties which place this
material as a good candidate for manufacturing type I capacitors or hyperfrequency resonators. The development of Base Metal Electrodes
Multi Layer Ceramic Capacitors (BME-MLCC) require a low sintering temperature to be co-sintered with a low cost metal such as copper or
silver. Unfortunately, BZN requires a high temperature (1350°C according to the literature) to reach a satisfactory density (>90% of the
theoretical one). The aim of this work is to lower the BZN sintering temperature to allow a co-sintering with copper or silver electrodes. For
this goal, different sintering agents (lithium salts and glass phases) have been tested on the nominal compound. It is shown that an addition of
10 molar% B2O3 combined with 5 molar% LiF authorises a sintering temperature lowering near to 350°C. If a slight non-stoichiometry in A
site is combined to these sintering agents, it is possible to reach a sintering temperature lower than 950°C without affecting the basic material
properties. For each composition obtained, the ceramic is characterised in terms of final density, microstructure and dielectric properties. The
silver co-sintering is also performed.
L0071 – Influence of the synthesis route on sol-gel SiO2-TiO2 (1:1) xerogels and powders
Five different sol-gel routes are used in order to synthesize mixed SiO2-TiO2 materials. Simple mixing of the Ti and Si precursors, prehydrolyzing
of TEOS, modification of the Ti alkoxide with acetic acid, isoamyl alcohol and acetylacetone lead to translucent gels with different
time of gelation. Different techniques such as TGA, DTA, XRD and IR spectroscopy are used to characterize each material. IR spectroscopy
revealed the presence of Si-O-Ti and Si-O-Si bonds for all the xerogels letting suppose a composite microstructure of the gels. Pre-hydrolyzing of
TEOS and modification of Ti alkoxide with isoamyl alcohol are the most appropriate routes to retain the anatase phase up to 1100°C.
L0060 – Processing and characterization of ultra-thin yttria-stabilized zirconia (YSZ) electrolytic films for SOFC
Sub-micron yttria-stabilized zirconia (YSZ) electrolyte layer was prepared by a liquid state deposition method and with an average thickness of
0.5 Am to improve the performance of the anode-supported solid oxide fuel cell (SOFC). The YSZ precursors, containing yttrium and zirconium
species and an additive, poly-vinyl-pyrrolidone (PVP), were spin-coated on a Ni/YSZ anode substrate. Several properties, including crystalline
phases, microstructures, and current-voltage (I -V) characteristics, were investigated. The thin film of 4 mol% Y2O3-doped ZrO2 (4YSZ)
consisted of cubic, tetragonal, and a trace of monoclinic phases, and showed a crack-free layer after sintering at 1300°C. The anode supported
SOFC, which consists of the Ni-YSZ anode, 4YSZ electrolyte, and Pt/Pd cathode, showed power densities of 477 mW/cm2 at 600°C, and 684
mW/cm2 at 800°C. Otherwise, the surface cracks of the other YSZ-coated samples (e.g. 8YSZ) can be repaired by a multi-coating method.
L0082 – Fabrication of gapless triangular micro-lens array
This study presents a new process to fabricate gapless triangular micro-lens array (GTMA) optical film. The process includes ultraviolet (UV)
lithography, photoresist reflow process, Ni-Co electroplating and hot embossing technique. After photoresist triangular column array is defined
by UV lithography, reflow technique is applied to melt photoresist triangular column array into the shape of triangular micro-lens array. With
this reflowed triangular micro-lens array, metal Ni-Co is deposited and covered uniformly on the triangular micro-lens array using electroplating
process. The growth rate of Ni-Co is controlled at 0.4-0.6 µm/min at electroplating current density of 1 A/dm2 (ampere square decimetre, ASD).
After this electroplating process, a mold of GTMA is obtained, which is served as the primary mold. Next, with passivation technique applied on
this primary mold's surface, a secondary mold is obtained by applying the electroplating process again. This secondary mold is served as master
for the subsequent hot embossing process to replicate the GTMA pattern onto polymeric material of polymethyl methacrylate (PMMA) sheet. The
Ni-Co mold with hardness over hardness of vicker (Hv) 650 is obtained. The stiffness and hardness of the mold play important roles in GTMA hot
embossing process. In addition, this PMMA-based GTMA film used as optical film offers a 100% fill factor and high optical coupling efficiency to
improve luminance. The optical measurement shows that this optical film with GTMA pattern increases 15.1% of luminance for backlight module
(BLM) of liquid crystal display (LCD).
L0070 – Proton conduction in ceria-doped Ba2In2O5 nanocrystalline ceramic at low temperature
Sintered pellets of Ce-doped Ba2In2O5 (BIC) were prepared from nanopowders. The electrical conductivities were measured using ac impedance
spectroscopy under different atmospheres and temperatures. The electrical conductivity of sintered BIC was found sensitive to environmental
humidity when the temperature was below 300°C. However, in the presence of hydrogen, the electrical conductivities were independent of water
content in the range of 0-30 vol%. The electrical conductivities of BIC were significantly affected by the presence of hydrogen in a temperature
range of 100-300°C. The estimated protonic transference number and the measured open circuit voltage suggested the existence of electronic
conduction. The coefficient of thermal expansion of BIC is 11.2x10^(-6) K-1 from 25 to 1250°C.
L0059 – High-temperature thermal characterization
L0081 – The rock salt oxide Li2MgTiO4: Type I dielectric and ionic conductor
The exploration of the Li-Ti-Mg-O system, using both sol-gel technique and solid state reaction method, allowed a new phase,
Li2MgTiO4, with disordered rock salt structure (a = 4.159 Å ) to be synthesized. The latter is shown to be a good type I dielectric
material, with a relative constant of 15 at high frequency and low dielectric loss (tand < 10^(-3)) over the temperature range - 60 to
160°C. It is also observed that the sintering temperature of this phase is strongly lowered by adopting the sol-gel technique
compared to solid state reaction (1150°C instead of 1300°C). Finally we show that this phase exhibits cationic conductivity above
400°C (s600°C = 9 x 10^(-5) S cm-1).
L0069 – A study on sintering aids for Sm0.2Ce0.8O1.9 electrolyte
In this study, an addition of Co oxide or Cu oxide to Sm0.2Ce0.8O1.9 (SDC) was studied to improve the sinterability of SDC. It has been found
that both Co and Cu oxide are very effective as sintering aids, and the SDC sintering temperature can be reduced from 1400°C without aids to
below 1000°C with only 1 at.% of either Cu oxide or Co oxide. As compared to the pure SDC, a slight decrease of ionic conductivity was observed
in SDC with Cu sintering aid. There is no obvious effect on electrochemical property of SDC with Co sintering aid under 2.5 at.%.
L0058 – The current detour effect observed on materials with random microstucture: experimental evidence from Li3xLa2/3-xTiO3 studied by impedance spectroscopy
Impedance spectroscopy (IS) has been used to study the influence on the low frequency part of the impedance diagrams of the microstructure of a
fast ionic conductor, Li3xLa2/3-xTiO3 with x = 0.10 (named hereafter LLTO). This oxide has been synthesised by sol-gel method. After synthesis,
the powder of LLTO displays a large distribution of grain size and agglomerates. The grain size distribution and the porosity of the ceramic have
been changed by heat-treatment from 600°C to 1200°C in air. The impedance spectra of these ceramics, recorded at different temperatures from
room temperature (RT) to 400°C, show a low-frequency depressed arc, which is characteristic of the grain boundary response of the ceramic.
Its shape depends strongly on the heat-treatment of the ceramic, and therefore, on its microstructure. It is a simple arc when the pellet is well
sintered but becomes very complex for non-sintered ceramics with high resistive grain boundary and pores. The observed "fish" shape indicates
the presence of current "detours effect" in the material. This effect means that current detours around blocking grain boundary and/or pores occur
to lower the impedance. Consequently, the brick layer model (BLM), which assumes an ideal microstructure, and then no current "detours effect",
can not be used to analyse these impedance data.
L0080 – A novel low temperature sintering process for PMnN-PZT ceramics
Samples with the composition of 0.07Pb(Mn1/3Nb2/3)O3-0.468PbZrO3-0.462PbTiO3 was prepared in this study. A novel process was adapted
to lower the sintering temperature without properties deterioration. The sintering process includes a vacuumed heating stage, a air-venting heating
stage, and a final sintering at 1050°C with certain holding time without PbO compensating atmosphere. The influence of holding time at the final
sintering stage on the characteristics of the ceramics was studied. The air-venting stage caused a large shrinkage (about 10%) and then slowing
down the shrinking rate when the sample was heated up from 800 to 1050°C. The relationships between the crystalline characteristics and physical
properties, such as microstructure, the mechanical quality factor (Qm), and electromechanical coupling factor (kp), are discussed in this paper.
L0068 – Electrical properties of low-density polyethylene/multiwalled carbon nanotube nanocomposites
Low-density polyethylene (LDPE)/multiwalled carbon nanotube (CNT) nanocomposites were prepared via melt compounding. The electrical
properties of LDPE/CNT nanocomposites as a function of CNT volume content, frequency and temperature were investigated. The results showed
that dielectric constant of LDPE/CNT nanocomposites increases slightly with increasing CNT content up to 1.9 vol.%. Thereafter, the dielectric
constant of the nanocomposites increases sharply. The dielectric constant of LDPE/3.6 vol.% CNT nanocomposite is more than two orders of
magnitude larger than that of pure LDPE. The frequency dependence of electrical properties of LDPE/3.6 vol.% CNT nanocomposite can be well
described by the percolation theory.
L0057 – Deformation of steel powder compacts during sintering: Correlation between macroscopic measurement and in situ microtomography analysis
Powder compacts obtained by warm pressing of steel powder containing lubricant were found to swell during a typical delubrication
cycle and shrink during sintering. The final dimensional changes of the denser compact were strongly anisotropic. Dilatometry measurements
showed that final deformation resulted from microstructure induced by prior die pressing and from various phenomena arising at
different stages of the cycle, each of them leading to a specific anisotropic effect. To corroborate this assumption the microstructure evolution
of the denser material throughout sintering has been observed using in situ synchrotron X-ray computed microtomography. In
addition to visual examination, quantitative analysis of 3D images consisted in searching for a relationship between the morphology
and the orientation of pores in 2D sections and measuring local strain with an image correlation technique. From this information a
schematic description of the main phenomena responsible for the deformation of steel powder compacts during sintering is proposed.
L0079 – The effects of the physical states of a simulated fission product on the linear thermal expansion of (U0.924Ce0.076)O2
The linear thermal expansions of an (U0.924Ce0.076)O2 pellet, doped a simulated fission product (Nd2O3 or Ru), were measured from room
temperature to 1673K in a flowing argon atmosphere using TMA. Nd2O3 and Ru represent the physical states of a fission product, a dissolved
oxide and a metallic precipitate, respectively. Using the measured data, the mean coefficients of a linear thermal expansion was obtained as a
function of the temperature, and the effects of the physical states of a simulated fission product on the thermal expansion were investigated.
In the case of the Nd2O3 forming a dissolved oxide, the thermal expansion of the sample increased and the increment was proportional to the
Nd contents, because the melting point of the Nd2O3 was lower than that of UO2 and although the metallic precipitate hardly affected the crystal
structure, the linear thermal expansion also increased with an increasing Ru contents.
L0067 – Low temperature sintering of ZnTiO3/TiO2 based dielectric with controlled temperature coefficient
Structure, microstructure and dielectric properties of ZnTiO3 and rutile TiO2 mixtures (ZnTiO3 + xTiO2 with x = 0, 0.02, 0.05, 0.1, 0.15 and 0.2)
sintered using ZnO-B2O3 glass phase (5 wt.% added) as sintering aid have been investigated. For all compounds, the sintering temperature achieves
900°C. The X-ray diffraction patterns indicate for x = 0.1 that the material is composed by three phases identified as ZnTiO3 hexagonal, TiO2
rutile and ZnO. The presence of ZnO is explained by the introduction of Ti into Zn site to form the (Zn1-xTix)TiO3+x solid solution in resulting
the departure of ZnO from the ZnTiO3 structure. The ZnTiO3 + 0.15TiO2 composition sintered at 900°C with glass addition exhibits attractive
dielectrics properties (Er = 23, tan(delta) < 10^(-3) and a temperature coefficient of the dielectric constant near zero (t = 0 ppm/°C)) at 1 MHz. It is also
shown that the introduction of TiO2 allows to tune the temperature coefficient of the permittivity. All these properties lead this system compatible
to manufacture silver based electrodes multilayer dielectrics devices.
L0056 – Piezo-spectroscopic characterization of alumina-aluminium titanate laminates
A multilayered alumina-aluminium titanate composite was prepared by a colloidal route from aqueous suspensions. The structure of the
laminate was symmetric and constituted of two external Al2O3 layers (width=1750 µm), one central Al2O3 layer (width=1200 µm) and
two intermediate thin (width=315-330 m) Al2O3-Al2TiO5 layers.
Additional monolithic materials with the same compositions as those of the layers were fabricated as reference materials. Young's modulus
of the monoliths was determined by three point bending. Dilatometry determinations were performed on green specimens, following the same
heating and cooling schedules as those used for sintering the laminate, in order to determine the actual dimensional changes on cooling after
sintering. The dimensional changes of the sintered specimens on heating and on cooling were also determined. Microscopic distributions
of residual stresses were evaluated by fluorescence piezo-spectroscopy, and they revealed the existence of weak tensile and compressive
hydrostatic stresses in the aluminium titanate and alumina layers, respectively. The level and sign of these stresses was in good agreement
with those predicted based on analysis of the Young's modulus and the dimensional variations during cooling after sintering of the monoliths
with the same compositions as those of the layers. Dimensional variations during cooling after sintering were different from those for sintered
materials, which presented hysteresis between heating and cooling. In spite of the presence of compressive residual stresses in the external
layers of the laminate, strength values of notched samples of the laminated specimens were lower than those for monoliths of the same
composition as the external layers.
L0078 – Development of Mg/Cu nanocomposites using microwave assisted rapid sintering
In the present study, magnesium composites containing different amounts of nano-size Cu particulates were successfully synthesized
using powder metallurgy (PM) technique incorporating microwave assisted two-directional sintering. The sintered specimens were hot
extruded and characterized in terms of physical, microstructural and mechanical properties. Microstructural characterization revealed
minimal porosity and the presence of a continuous network of nano-size Cu particulates and Mg2Cu intermetallic phase decorating
the particle boundaries of the metal matrix. Coefficient of thermal expansion (CTE) value of magnesium matrix was improved marginally
with the addition of nano-size Cu particulates. Mechanical characterization revealed that the addition of nano-size Cu particulates lead
to an increase in hardness, elastic modulus, 0.2% yield strength (YS), ultimate tensile strength (UTS) and work of fracture of the matrix.
An attempt is made in the present study to correlate the effect of increasing amount of nano-size Cu reinforcement on the microstructure
and properties of monolithic magnesium.
L0066 – Synthesis and sintering of a monazite-brabantite solid solution ceramic for nuclear waste storage
Various geological arguments suggest that monazite can be an interesting waste-form for actinides such as Np, Pu, Cm and Am. We
set up a simple procedure for making dense pellets of monazite-brabantite solid-solution ceramics with composition Ca0.092Th0.092
Ce0.089La0.727PO4. It consists of co-milling CaCO3, ThO2, CeO2, La2O3, and NH4H2PO4, 1250°C calcination, milling, cold-pressing, and
sintering at 1450°C for 4 h. X-ray investigations showed that the reaction scheme from oxides to monazite is complex and involves
various P+La-based intermediate compounds. The final density of the the product is around 95% of the theoretical density. The texture
is homogeneous with a typical grain of size 5-20 mm. This process is designed to be adapted to hot cells and telemanipulators.
L0055 – Ce4+ modified cordierite ceramics
A dense, low thermal expansion cordierite ceramic was prepared by the co-precipitation method and Ce4+ addition. Ce4+ addition can
inhibit m-cordierite crystallization and improve a-cordierite crystallization. Adding 3.2 wt.% Ce4+ enables density and mechanical strength to
reach maximum values with a minor increase in thermal expansion coefficient.
L0076 – Modelling of the grain growth and the densification of SnO2-based ceramics
This work consisted in the kinetic study of grain growth and densification processes for SnO2 and Sn0.94Zr0.06O2 ceramics between 1100 and
From dilatometric experiments, it appeared that zirconia additions inhibited the final densification rate. For pure SnO2, the rate limiting step of
the densification mechanism would correspond to the grain boundary or volume diffusion. From normal grain growth kinetics, the corresponding
limiting step has been identified, i.e. either the surface diffusion in pores or grain boundary diffusion for ZrO2 free-SnO2 and Sn0.94Zr0.06O2,
All of these results permit establishing the corresponding sintering map. For pure SnO2 ceramic, the experimental data have been well restored
L0065 – Effects of solid fission products forming dissolved oxide (Nd) and metallic precipitate (Ru) on the thermal conductivity of uranium base oxide fuel
The effects of solid fission products on the thermal conductivity of uranium base oxide nuclear fuel were experimentally investigated. Neodymium
(Nd) and ruthenium (Ru) were added to represent the physical states of solid fission products such as 'dissolved oxide' and 'metallic precipitate',
respectively. Thermal conductivity was determined on the basis of the thermal diffusivity, density and specific heat values. The effects of the
additives on the thermal conductivity were quantified in the form of the thermal resistivity equation - the reciprocal of the phonon conduction
equation - which was determined from the measured data. It is concluded that the thermal conductivity of the irradiated nuclear fuel is affected by
both the 'dissolved oxide' and the 'metallic precipitate', however, the effects are in the opposite direction and the 'dissolved oxide' influences the
thermal conductivity more significantly than that of the 'metallic precipitate'.
L0075 – Effects of the sintering atmosphere on Nb-based dielectrics
The effects of a forming atmosphere on the stability, the sintering and the dielectric properties of Ba5Nb4O15, BaNb2O6, ZnNb2O6 and
Zn3Nb2O8 ceramics were investigated, because of the primary importance of the sintering atmosphere in relation to copper sintering. These Nbbased
materials were sintered in air and in Ar/H210%. Zn-containing samples are very sensitive to the reductive atmosphere. ZnO volatilises at
800-850°C and the resulting compound does not exhibit the expected properties. BaNb2O6 and Ba5Nb4O15 are more stable in term of relative
weight loss. Nevertheless, the phase analysis reveals a modification of the BaNb2O6 phase, what induces the degradation of the dielectric property
stability versus temperature. The properties of Ba5Nb4O15 are not modified by a sintering in reductive atmosphere. A relative permittivity of 38.8, a
permittivity temperature coefficient of -150 ppm°C-1 and an insulating resistivity of 10^10.9 V cm were obtained for this latter.
L0064 – Microwave synthesis and characterization of metastable (Al/Ti) and hybrid (Al/Ti + SiC) composites
Two-directional microwave assisted rapid sinteringwas carried out to fabricate Al/Ti metastable composites and Al/(Ti + SiC) hybrid composites.
The length scale of Ti was in microns (20µm) and of SiC in nanometers (50 nm). Microstructural characterization revealed uniform distribution
of Ti particulates and SiC nanoparticulates in the Al matrix, relatively low amount of porosity and good matrix-reinforcement interfacial integrity.
Coefficient of thermal expansion of the Al matrix reduced due to the presence of Ti and Ti + SiC reinforcements. The results revealed that addition
of SiC nanoparticulates to Al-Ti formulations assisted in increasing microhardness, macrohardness, Al-Ti interfacial hardness, 0.2% YS and UTS
while the ductility was marginally affected. Particular emphasis was placed to study the feasibility of using hybrid reinforcements in the Al matrix
synthesized by using microwaves.
L0074 – Preparation and properties of dense Ce0.9Gd0.1O(2-d) ceramics for use as electrolytes in IT-SOFCs
Gd-doped ceria solid solutions have been recognized to be leading electrolytes for use in intermediate-temperature fuel cells. In this communication,
it reported on the preparation, solubility and densification of Ce0.9Gd0.1O(2-d) ceramics derived from carbonate coprecipitation. The
dissolution of Gd2O3 in CeO2 lattice was identified to complete during coprecipitation process by studying lattice parameter against temperature.
The calcining temperature was found to have a significant influence on the densification behavior and final sintered density for the carbonatecoprecipitated
powder. The samples prepared from the powder calcined at <700°C had an expansion at ~1250 to 1400°C during sintering, and
thus lowered sintered density. 800°C was identified to be an optimal calcining temperature for carbonate-coprecipitated powder. The powder
calcined at 800°C for 2 h had a mean crystalline size of ~25 nm with nearly spherical shape and narrow particle-size distribution, which had
a maximum densification rate at ~1190°C. This temperature (of maximum densification rate) could further be reduced to ~1080°C for the
carbonate-coprecipitated powder by adding 0.5 at.% FeO1.5 (atomic ratio). At 1200°C for 5 h, over 98% relative density with an average grain
size of ~1.2µm was obtained for the 0.5 at.% Fe-loaded Ce0.9Gd0.1O(2-d) ceramics. Fe loading was also found to have a positive effect on grain
boundary conductivity of Ce0.9Gd0.1O(2-d) ceramics. An increase in the grain boundary conduction by over two times was achieved in the present
work for the 0.5 at.% Fe-loaded Ce0.9Gd0.1O(2-d) ceramics.
L0063 – Rheological behaviour of kaolin/talc/alumina suspensions for manufacturing cordierite foams
This paper deals with the preparation and rheological charaterization of concentrated suspensions
(40 vol.% solids) of mixtures of kaolin/talc/alumina to relative weight contents of 40/43.8/16.2,
respectively. These concentrated suspensions were thixotropic and viscosus, the rheological
properties being largely influenced by a number of processing parameters, the most relevant being
the nature and content of deflocculant and the pH value. Best results were obtained for a
polyacrylic-based polyelectrolyte and pH 11. Green densities of 59 % of TD were obtained.
Dynamic and static sintering studies were performed and the analysis of the resulting phases was
made by XRD. From these tests it was concluded that cordierite phase needed a thermal treatment
of 1300ºC to be formed. The sintered slip cast materials have a large residual porosity because of
the coarse particle size of the raw materals. Macroporous cordierite foams are obtained by
impregnation of polyurethane foam into the optimized slip and heating at 1350ºC/1h with a burning
out step at 550ºC/30 min.
L0073 – Abnormal thermal expansion and thermal stability of Ti3Al(1-x)SixC2 solid solutions
Ti3Al(1-x)SixC2 solid solutions exhibited abnormal high coefficients of thermal expansion at temperatures of >940°C during heating,
which was ascribed to the precipitation of Si as Ti5Si3. Ti5Si3 phase usually located at the grain boundaries of the solid solutions.
L0062 – Modelling WC-Co sintering shrinkage – Effect of carbide grain size and cobalt content
Phenomenological models based on the constitutive parameters uniaxial viscosity, viscous equivalent of Poisson's ratio and sintering stress are
used to describe WC-Co sintering shrinkage. Shrinkage is divided into three subsequent stages. The influences of carbide grain size and cobalt
content are accounted for and model parameters numerically adjusted to dilatometer results. The model successfully represents published shrinkage
data for different materials and milling procedures.
L0072 – Indentation creep behavior of a Zr-based bulk metallic glass
The deformation behavior of a Zr44Ti11Cu10Ni10Be25 bulk metallic glass (LM-1B) was studied in the supercooled liquid region by indentation
creep test. Before indentation the glass transition and the crystallization temperatures were determined by calorimeter as 625 and 725 K, respectively.
The phases formed during crystallization were identified by X-ray diffraction. The indentation creep experiments were carried out at different
temperatures and loads. It was found that the creep can be regarded as Newtonian flow at strain rates between 5x10^(-5) and 5x10^(-4) s-1. The
values of the viscosity and the activation energy of deformation were determined in the temperature range of 667-687 K.
L0061 – Wetting, densification and phase transformation of La2O3/A2O3/B2O3-based glass-ceramics
A lead-free, non-alkali La2O3-Al2O3-B2O3 (LAB) glass with Al2O3 filler had been investigated for low temperature co-firing ceramic (LTCC)
application. The glass forming window and several physical properties of the LAB systems were investigated by ICP, TMA, XRD, DSC,
and SEM/EDS. The results show that the densification and crystallization temperatures of LAB/Al2O3 were between 700°C and 950°C and
depended greatly on the formulation. Crystalline phase LaBO3 (LB) and LaAl2B3O9 (L2A3B) crystallized starting at 825°C and 925°C,
respectively. High degree of densification and crystallization of one glass-Al2O3 composition (L30A) was observed with the microstructure
composed of tabular L2A3B grains interlocking with submicron Al2O3 and LB grains.
L0106 – The mechanical behavior of magnesium alloy AZ91 reinforced with fine copper particulates
In this study, a hybrid composite based on magnesium alloy AZ91A reinforced with copper particulateswas fabricated using the disintegrated
melt deposition (DMD) processing technique followed by hot extrusion. Microstructural characterization of the as-extruded composite sample
revealed a near uniform distribution of the copper particulates and other intermetallic phases through the magnesium alloy metal matrix, good
integrity at the copper-magnesium alloy matrix interfaces and evidence of minimal porosity. Mechanical property quantification revealed that
addition of copper particulates resulted in a significant increase in elastic modulus, 0.2% offset yield strength and ultimate tensile strength of the
composite material. However, ductility of the composite was marginally affected when compared to the unreinforced monolithic counterpart.
The overall mechanical properties of AZ91A/Cu composite were found to be higher than the silicon carbide particulate reinforced AZ91
composite, even for higher volume fractions of the particulate reinforcement. Influence of copper in the matrix of magnesium alloy AZ91A
is examined in light of intrinsic microstructural features and mechanical properties of the composite.
L0095 – Effect of ZrO2 additions on sintering of SnO2-based ceramics
The effect of zirconia additions on sintering of CoO doped tin dioxide has been investigated in the temperature range 1100-
1250°C. A first study showed that the substitution of tin by zirconium reduces significantly the volatilisation rate of SnO2 for
temperatures greater than 1400°C. It appeared that the zirconium content increase inhibits the densification kinetics of SnO2-based
ceramics. Indeed, the relative density did not exceed 93% for a Zr content lower than 6 mol% in the Sn(1-x)ZrxO2 solid solution.
This negative effect can be imputed to the elastic distortions caused by the introduction of Zr in the tin dioxide lattice. So, the
diffusion rate of point defects such as oxygen or cobalt ions is lowered.
L0105 – Experimental and numerical analysis of the deformation of ferrite segments during sintering
The thermo-mechanical behaviour of hard ferrite powder compacts at high temperature is investigated with a view to simulating
dimensional changes occurring during sintering of industrial components. Emphasis is laid on the anisotropy in both shrinkage and
viscosity, which is induced by the prior pressing operation performed under magnetic field. Anisotropic shrinkage and viscosity are described
according to an original approach based on an orthotropic thermo-elastic equation, which assumes an analogy between the thermal and
elastic terms of this equation and the viscous and free sintering deformations. Finite element calculations using this constitutive equation
are then carried out on two industrial parts. The comparison between the obtained numerical results and experimental measurements proves
the relevance of the proposed model.
L0094 – Microstructural evolution of Y2O3 and MgAl2O4 ODS EUROFER steels during their elaboration by mechanical milling and hot isostatic pressing
Different ODS EUROFER steels reinforced with Y2O3 and MgAl2O4 were elaborated by mechanical milling and hot
isostatic pressing. Good compromise between strength and ductility could be obtained but the impact properties remain
low (especially for the Y2O3 ODS steel). The materials were structurally characterized at each step of the elaboration.
During milling, the martensite laths of the steel are transformed into nano-metric ferritic grains and the Y2O3 oxides
dissolve (but not the MgAl2O4 spinels). After the HIP, all the ODS steels remain ferritic with micrometric grains, surrounded
by nano-metric grains for the Y2O3 ODS steels. The mechanisms in the Y2O3 ODS steels are complex: the
Y2O3 oxides re-precipitate as nano-Y2O3 particles that impede a complete austenitization during the HIP. The quenchability
of the ODS steels is modified by the milling process, the oxide nature and the oxide content. Eventually, the
advantages and drawbacks of each oxide type are discussed.
L0104 – Rare earth phosphate powders RePO4 . nH2O (Re=La, Ce or Y) II. Thermal behavior
The thermal behavior, thermostructural and morphological changes, of rare earth phosphate powders RePO4 . nH2O (Re=La, Ce
or Y) was investigated up to 1500°C using high temperature X-ray diffraction, FT-infrared and Raman spectroscopies and
thermogravimetry coupled with differential thermal analysis. The hydration water of the compounds was zeolitic (for Re=La or Ce)
or coordinated (for Re=Y) and was associated with a divariant or a monovariant equilibrium of dehydration, respectively. The high
temperature anhydrous monoclinic phase LaPO4 or CePO4 formed irreversibly at about 750°C after the total dehydration of the
hexagonal hydrated structure while the dehydration of the monoclinic YPO4 . 2H2O phase began from about 190°C with its
simultaneous decomposition into tetragonal YPO4. A polytrioxophosphate secondary minor phase Re(PO3)3 resulting from
adsorbed H3PO4 was formed at 950°C and decomposed at 1350°C. The particle morphology did not change with the temperature
but grain coalescence occurred below 1000°C.
L0093 – Thermal stability and mechanical properties of a Zr-based bulk amorphous alloy
The thermal and mechanical properties of a Zr-Al-Cu-Ti-Ni bulk metallic glass were investigated. The glass transition and the crystallization
were studied by calorimetry and X-ray diffraction. It was found that the crystallization occurred in two steps. The precipitating phases, and the
activation energies were determined. It was established that the crystallization was controlled by the diffusion of the alloying Cu and Ni atoms.
The creep behavior was investigated by indentation tests. The viscosity and the activation energy of the deformation process determined from
indentation were in reasonable agreement with those obtained by compression tests.
L0103 – Ce0.8Gd0.2O(2-d) ceramics derived from commercial submicron-sized CeO2 and Gd2O3 powders for use as electrolytes in solid oxide fuel cells
Twenty percentage of Gd2O3-doped ceria solid solution has been prepared as an electrolyte for solid oxide fuel cells via the conventional
mixed-oxide method from high-purity commercial CeO2 and Gd2O3. The solubility of Gd2O3 in CeO2 in the temperature range of
1300-1700°C has been examined based on the measurements of the lattice parameter. It is found that the dissolution of Gd2O3 in CeO2 is
completed at 1600°C for 5 h. The addition of Gd2O3 increases sintering temperature, retards densification, and also depresses grain growth
as compared with undoped CeO2. The sample sintered at 1550°C for 5 h has the highest grain boundary conductivity, while the highest
grain interior conductivity is achieved for the sample sintered at 1600°C for 5 h. It is also observed that below 500°C, the maximum total
conductivity is exhibited by the former sample, but above 500°C, for the latter one.
L0092 – Improvements in sintered density and dimensional stability of powder injection-molded 316L compacts by adjusting the alloying compositions
Powder injection molding is a process that provides advantages when making small parts with high density and complicated shapes.
However, dimensional control of powder injection-molded stainless steel parts is difficult due to the presence of the liquid phase and the
large amount of shrinkage that occurs during sintering. This study examines whether such a problem can be overcome through adjustments
in the alloy composition and by making use of Thermo-Calc analysis. The results show that, with an increase in the molybdenum
content up to the maximum limit according to existing specifications, a compact can be sintered to high densities without the presence of
the liquid phase, while maintaining it in the dual-phase region of gamma + delta. In addition, dimensional control is improved. A slower heating
rate is also found to be beneficial. These results are explained through dilatometric analysis and phase diagrams that are calculated using
the Thermo-Calc program.
L0102 – Increasing elastic modulus, strength and CTE of AZ91 by reinforcing pure magnesium with elemental copper
Heat-treatable AZ91 and 3.9 vol.% copper particulate reinforced magnesium composite was synthesized using an innovative disintegrated
melt deposition (DMD) technique followed by hot extrusion. Microstructural characterization of the composite material revealed retention
and uniform distribution of reinforcement with defect free interface with the matrix. Physical properties characterization revealed improved
dimensional stability of composite when compared to AZ91. Mechanical properties characterization revealed an increase in average values of
modulus, 0.2% yield strength and ultimate tensile strength of un-heat-treated composite when compared to T6 heat-treated AZ91 while the
ductility was adversely affected. An attempt is made in the present study to compare the microstructural, physical and mechanical properties
of Mg/Cup composite with that of the commercially used AZ91 alloy.
L0091 – Studies of Fe-Co based perovskite cathodes with different A-site cations
Iron-cobalt based perovskite cathodes with different A-site cations ((Ln0.6Sr0.4)0.99Fe0.8Co0.2O(3-d), where Ln is La, Pr, Sm or Gd) have been
synthesised, characterised by a powder XRD, dilatometry, 4-point DC conductivity measurements, and electrochemical impedance spectroscopy
(EIS) on cone shaped electrodes. In addition to this scanning electron microscopy (SEM) was used to characterise the bars. XRD revealed that
only the La-containing perovskite was hexagonal. The Pr and Sm perovskites were orthorhombic. The gadolinium-based perovskite was a two
phase system consisting of an orthorhombic and a cubic perovskite phase. The thermal expansion coefficient (TEC) increased systematically with
a decrease in the size of the A-site cation until the gadolinium-containing perovskite where the TEC decreases abruptly. The total electric
conductivity was the highest for the La-based perovskite and the lowest for the Gd-based perovskite as determined by 4-point DC conductivity
measurements on bars. A clear correlation between the size of the A-site cation and the electrochemical performance was revealed, as the area
specific resistance (ASR) was the lowest for the compounds with the smallest A-site cation. This might be explained on the background of the
creation of a two-phase structure with a unique microstructure when the size of the A-site cation is lowered, or that one of the phases has a high
electro-catalytic activity towards the electrochemical reduction of oxygen.
L0101 – Mullite phase formation in oxide mixtures in the presence of Y2O3, La2O3 and CeO2
The effect of oxides (Y2O3, La2O3, and CeO2), on phase formation of mullite, reaction sequence and microstructure evolution, in the
mixtures of Al2O3 and SiO2, has been investigated. All three dopants showed a positive effect on the mullitization behavior, lowering the
mullite formation temperature by about 100°C. The improved mullitization behavior was attributed to the formation of the low-viscosity
liquid phase due to the addition of dopants. The reaction sequence was different in the three doping cases. Two types of yttrium silicate were
found in the samples doped with Y2O3, with one being favored at low temperature and another at high temperature. No reaction was observed
between CeO2 and Al2O3 or SiO2, while La2O3 was not detected by the X-ray diffraction (XRD) measurement for all doping levels. The
samples with La2O3 had the best densification behavior among the three doping cases, while the effect of CeO2 on densification was slightly
better than that of Y2O3. The difference in the effects of the three oxides on the mullitization and densification behavior of the doped samples
implied the difference in the characteristics of the low-viscosity glass phases formed at high temperatures.
L0090 – Physical properties of BaMg(1/3)Nb(2/3)O3-BaCo(1/3)Nb(2/3)O3 solid solutions
Structural, electric and magnetic properties of Ba3Mg(1-x)CoxNb2O9 based dielectric ceramic compounds have been studied. The samples, prepared
by a solid state reaction method, were characterised by X-ray powder diffraction (XRPD), electron microscopy (SEM), dielectric (epsilon(T)) and magnetic
measurements (khi-1(T)). The XRPD analyses showed that the crystal structure of these compounds does change by the increase of substitution degree,
passing froma superstructure hexagonal-type, P3m1 (no. 164), space group (SG) to a simple structure cubic-type, Pm3m (no. 221), SG. However, the
evolution of the elementary unit cell lattice parameter can be followed and it exhibit a linear increasing tendency with increase in the substitution,
indicating the existence of a solid solution through out the investigated range of substitution (0-1). Themicrostructure analysis shows a variation inthe
grain size and also the porosity of the samples with the degree of substitution. The results are in good agreement with that of dielectricmeasurements,
which also showed that the dielectric constant (epsilon) increases with the increase of cobalt content. The magnetic characterization of cobalt substituted
samples showed an antiferromagnetic type super-exchange interaction between thesemagnetic ions. At the same time, the values of effective magnetic
momentum (µeff) are close to the value that corresponds to Co2+ free ions. The study highlights the possibility of modelling these materials by
substitutions, in order to improve properties of negative-positive-zero (NPO) type dielectric applications.
L0100 – Structure, nonstoichiometry and magnetic properties of the perovskites Sr(1-x)CaxMnO(3-d)
The structural, thermal and magnetic properties of the perovskite-type alkaline-earth manganites of the series Sr(1-x)CaxMnO(3-d) (0 <
x < 1) were investigated. SrMnO(3-d) forms a hexagonal perovskite lattice and shows a first-order transformation to a highly defective cubic
high-temperature modification. By substituting Ca for Sr (x > 0.25) the hexagonal perovskite is suppressed and a cubic (or orthorhombic)
lattice becomes stabilized for all temperatures. For x = 0.5 and 0.75 cubic perovskites with a large nonstoichiometry (e.g., d = 0.25 for
x = 0.5) are obtained at 1400°C. The defective perovskites are prepared by either quenching from high temperature or by cooling in an inert
atmosphere. The oxygen vacancies are easily filled by subsequent reoxidation at low temperature (400-600°C) and stoichiometric samples
are obtained. Orthorhombic perovskites are formed at T < 1200°C with the nonstoichiometry d increasing with increasing temperature (e.g.,
d = 0.06 at 1000°C and d = 0.14 at 1200°C for x = 0.5). Slow cooling in air results in almost complete reoxidation (d = 0). CaMnO(3-d) is
an orthorhombic perovskite with a large range of nonstoichiometry (0 < d < 0.30). The cubic to hexagonal phase transformation of the Sr-rich
samples is accompanied by a large expansion of the lattice that is reduced by Ca substitution. The Ca/Sr-manganites are antiferromagnets
with TN of 170 K for x = 0.5 and d = 0.02 and 120 K for x = 1 and d = 0.05.
L0088 – Mechanical and thermal expansion behavior of hipped aluminum-TiB2 composites
Aluminum-TiB2 composites reinforced with 5-20 vol.% ceramic particles were prepared by powder metallurgy (PM) method. Hot isostatic
pressing was employed to consolidate the green PM products. The microstructure of metal matrix composites (MMCs) was found to depend
greatly on the relative particle size (RPS) ratio between the aluminum and ceramic particles. Microstructural examination revealed that RPS
value of 0.56 favors both the densification of MMC compacts and better uniform distribution of ceramic particles. Tensile measurements
showed that the Young's modulus and ultimate tensile strength of the Al-TiB2p MMCs tend to increase with increasing TiB2p volume content
at the expense of tensile ductility. Thermal expansion property of hipped MMCs was measured in the temperature range from 85 to 600°C.
The results showed that the increase in the volume fraction of TiB2 reinforcement reduces the coefficient of thermal expansion (CTE) of the
Al-TiB2 composites. Moreover, the CTE versus temperature plots exhibited an apparent peak minimum at ~380°C during the first heating
stage for the composites reinforced with TiB2 >15 vol.%. This peak corresponds to the onset of relaxation for the compressive stress, leading
to the Al matrix to deform plastically.
L0099 – Ductility improvement of Ni-added molybdenum compacts through the addition of Cu and Fe powders
The sintered density of molybdenum can be significantly improved through the addition of a small amount of nickel. However,
such addition impairs the ductility due to the formation of a NiMo intermetallic compound at the grain boundaries. This makes the
plastic deformation process, such as rolling, drawing, and forging, impossible. This study shows that when copper is added, the sintered
density can be further increased, but, not the ductility. This ductility problem of the Mo-Ni-Cu system can be improved when
a small amount of iron is added and when the total amount of the alloying Ni, Cu, and Fe is over 6wt%, such as in the Mo-4Ni-
1Cu-1Fe system. Such improvement is attributed to the elimination of the brittle NiMo compounds in the matrix.
L0087 – Improving the performance of lead-free solder reinforced with multi-walled carbon nanotubes
In this study, varying weight fractions of multi-walled carbon nanotubes were successfully incorporated into 95.8Sn-3.5Ag-0.7Cu solder, to
synthesize novel lead-free composite solders. The composite solders were synthesized via the powder metallurgy route of: blending, compaction,
sintering and extrusion. The extruded materials were then characterized for their physical, thermal and mechanical properties. With the addition
of increasing weight percentage of carbon nanotubes, the composite solders experienced a corresponding decrease in density values and wetting
property improved. The melting temperatures of the composite solders were found to be unchanged with the carbon nanotube additions. Thermomechanical
analysis of the composites also showed that the presence of reinforcements decreased the average coefficient of thermal expansion of
the solder matrix. An improvement in the mechanical properties was also recorded with the presence of increasing carbon nanotubes. An attempt
was made, to correlate the increasing presence of reinforcements with the physical, thermal and mechanical properties obtained.
L0109 – The synthesis mechanism of Ca3Al2O6 from soft mechanochemically activated precursors studied by time-resolved neutron diffraction up to 1000°C
The reaction pathway for the Ca3Al2O6 formation up to 1300°C, from mechanochemically treated mixtures of amorphous
aluminum hydroxide and CaCO3; was studied in situ by differential thermal analysis, constant heating rate dilatometry and timeresolved
neutron powder diffraction. The experiment was carried out, in an open system, on a sample with the nominal Ca3Al2O6
stoichiometry. The results obtained by neutron diffractometry and thermal analysis were in good agreement with the data obtained
by scanning electron microscopy and X-ray diffraction on heat-treated and-quenched samples. The synthesis path implied the
formation of cryptocrystalline Al2O3; crystalline CaO, CaAl2O4 and Ca12Al14O33 as transitory phases. Finally the nucleation and
growth of the single phase Ca3Al2O6 took place at 1300°C and exhibited porous structure due to CO2 and H2O release.
L0098 – Correlation between densification rate and microstructural evolution for pure alpha alumina
Correlation between microstructural evolution and macroscopic measurements has been investigated on pure alpha alumina
under non-isothermal conditions. The densification of different as-received and milled powders of alumina has been monitored
during sintering. Densification rate curves as a function of relative density are sensitive to microstructure, such as initial parameters
of microstructure (agglomeration, pore size, heterogeneities), and heating schedule (thermal pre-treatment, heating rate). Densifi-
cation rate curves can be correlated with microstructural evolution during overall sintering and are expected to be a good help to
choose raw materials.
L0086 – Evidence of the formation of a new rock-salt type compound Li2MgTiO4 and of its role on the properties of the Li doped MgTiO3
This work deals with the sintering of MgTiO3 in presence of Lithium salt and more precisely with lithium halide. These last sintering agents lead
to the formation of a new rock-salt type structure Li2MgTiO4. This new phase was synthesized by a classical solid-state route and their electric
and dielectric properties were characterize. The formed material is a type I dielectric material with a permittivity close to 12 with dielectric losses
inferiors to 0.3% in the range of -50 to 150°C. X-ray diffraction and investigation by TEM were also performed. The influences of the formation
of this new phase on the properties of MgTiO3 are described here.
L0108 – Effect of transition metal oxides on densification and electrical properties of Si-containing Ce0.8Gd0.2O(2-d) ceramics
Ce0.8Gd0.2O(2-d) (CGO20) ceramic has been considered as one of the most promising electrolytes for intermediate temperature (IT) fuel
cells. It has been reported that some transition metal oxides (TMO), such as MnO2, Fe2O3 and Co3O4, are effective sintering aids for the
densification of ceria-based electrolytes. However, very little information is available regarding the effect of TMO addition on the electrical
properties of Si-containing CGO20 ceramics. In this study, 0.5 at.% (atomic percent) TMOs have been loaded into the CGO20 with ~30
ppm (pure) and ~200 ppm (impure) SiO2, respectively, and the sintering behavior and ionic conductivity have been investigated. It has been
found that Co3O4 is the most effective sintering aid, and the sintering temperature of CGO20 can be reduced by over 200°C by adding 0.5
at.% CoO4/3. All the TMOs used show a slight effect on the grain-boundary (GB) conductivity of the pure CGO20. However, SiO2 additions,
together with MnO2 and Co3O4, have found to be extremely detrimental to the GB conduction of CGO20. As compared to the impure
CGO20, the GB resistance has been increased by over six times for the impure one with addition of only 0.5 at.% CoO4/3. On the other hand,
in contrast to the Mn or Co doping case, small addition of Fe2O3 has a scavenging effect on SiO2 impurity, and significantly improves the GB
conduction of the impure CGO20. Therefore, Fe2O3 could be used as an effective sintering aid, as well as a grain-boundary scavenger for
SiO2 contaminated ceria-based electrolytes.
L0097 – Synthesis of fine La0.8Sr0.2MnO3 powder by different ways
La0.8Sr0.2MnO3 (LSMO) powders were successfully synthesized by three routes (sol-gel, spray dryer and conventional solid state
method). The precursors were characterized by particle size analysis, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The
sintering stage of all powders was also investigated by dilatometer. Finally, the sintered LSMO ceramics have been investigated magnetically
and electrically in view to study the ferromagnetic-paramagnetic and/or metal-insulator transition. The magnetoresistance MR up to 42%
above room temperature has been observed.
L0085 – Thermal expansion of near stoichiometric (U,Er)O2 solid solutions
Thermal expansions of (U,Er)O2 solid solutions were investigated between room temperature and 1673 K by using a thermo-mechanical
analyzer. Lattice parameters of the (U,Er)O2 pellets are lower than that of UO2 and they decrease as the Er contents increase. The linear thermal
expansion and average thermal expansion coefficients of (U,Er)O2 are higher than that of UO2. For the temperature range from room temperature
to 1673 K, the average thermal expansion coefficient values for UO2 and (U0.8Er0.2)O2 are 10.94x10^(-6) and 11.42x10^(-6) K-1, respectively.
L0107 – The kinetics of surface area reduction during isothermal sintering of hydroxyapatite adsorbent
The behaviour of non-stoichiometric hydroxyapatite (HA) during the calcination in a solid bed was investigated. The structural properties
are described in terms of the specific surface area. Calcination led to a significant decrease of the specific surface area by particle coalescence
and densification. Hydroxyapatite begins to shrink near 780°C and reaches 97% theoretical density at 1100°C. The specific surface area
and density variations are caused both by sintering and chemical reaction. Sintering data from these solids were correlated as a function of
time and temperature. The rate of sintering is assumed to obey an Arrhenius equation. These results are compared with a number of literature
models describing the mechanism of sintering kinetics using the specific surface area, and a good agreement is observed. The kinetic equation
used is based on sintering driven by the curvature gradient in the interparticle neck region associated with initial stage sintering. Then, the
decline in specific surface area is accurately described by the empirical equation of the form dS/dt = -B(T)k^b. The changing value of b,
also known as the "order" of the reaction, suggests that the diffusion mechanism for loss of surface area may be a function of the temperature.
L0096 – Preparation of spherical zirconia powder in microemulsion system and its densification behavior
The water droplets in the microemulsion system of cyclohexane/water/TritonX-100/hexyl alcohol can act as the nano-reactors
which solubilize zirconium oxychloride and ammonia separately. The precipitation reactions will take place in the confined spaces
determined by the droplets size. The minute original reactors help us obtain nano-size spherical zirconia amorphous powder with
uniform diameter distribution and weak aggregate. Such powder begins to crystallize at the temperature about 475°C, and its
shrinkage of densification will be elementarily finished from 1080 to 1280°C. The powder is formed by dry pressing process. The
99% relative density and 100% tetragonal phase can be obtained when the green body is sintered at 1400°C for 2 h.
L0084 – Development of a novel hybrid aluminum-based composite with enhanced properties
In the present study, a novel aluminum-based hybrid composite containing titanium particulates (discontinuous/particulates reinforcement) and
iron mesh (continuous/interconnected reinforcement)was synthesized using a solidification processing route involving disintegrated melt deposition
coupled with hot extrusion. Microstructural characterization studies conducted on hybrid composite revealed reduced grain size (~44%) when
compared to monolithic aluminum, uniform distribution of unreacted and reacted titanium in matrix, and absence of reaction products at the
iron-wire/aluminum matrix interface. Results of properties characterization revealed that the presence of hybrid reinforcement led to a reduction
in coefficient of thermal expansion (~7.6%) and an increase in hardness, elastic modulus (~10%), 0.2% yield strength (20%) and ultimate tensile
strength (~27%). The enhancement in properties realized in hybrid composite was found to be much higher when compared to conventional Al/SiC
composite formulations containing relatively higher weight percentages of SiC particulates.
L0138 – Thermal Properties of Maleated Polyethylene/Layered Silicate Nanocomposites
Nanocomposites are a new class of composites in which the reinforcing phase dimensions are on the order of nanometer scale. In particular, the layered silicates are considered to be good candidates for the preparation of polymerinorganic nanocomposites. The mechanical and thermal properties of polymer can be altered by adding a few vol% of the nano-particles. The effect of the nano-sized particles on thermophysical properties such as melting and crystallization, coefficient of thermal expansion, and thermal conductivity was studied. After preparing the PEMA/layered silicate nanocomposites, the thermophysical properties were investigated by the differential scanning calorimetry and 3? methods. The content of layered silicate was varied from 0.5 to 5 vol%.
L0127 – Influence of synthesis route on morphology and conduction behavior of BaCe0.8Y0.2O32?
In this article, the role of the preparation route and calcinations temperature on the thermal expansion and conductivity of BaCe0.8Y0.2O3-d (BCY) has been studied. In particular, the samples were synthesized by means of the solid-state reaction and by a sol–gel route. BCY has been suggested as proton conducting electrolyte for intermediate-temperature solid oxide fuel cells (IT-SOFCs). Proton conductivity strongly depends on the densification of the material as well as the crystal structure, which is generally influenced by the preparation procedure. It was found that a single phase material could be achieved at 1000 C for the samples prepared through the sol–gel route with *96% packing density. In case of ceramic route, single phase could be obtained at higher temperatures (1200 C) and does not lead to good density values. The ceramic synthesis produces BCY material in cubic symmetry where as the gel–citrate complexation route leads to homogenous orthorhombic BCY. The conductivity measurements of sample synthesized by two different routes were investigated by means of impedance spectroscopy and electron
microscopy. A comparative study of thermal expansion behavior of BCY synthesized by different route was carried out.