bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of Scanning Microwave Technology for Ceramics in Extreme Environments
Authors: Little Jr. Jack R.
Published: October 2010

Advanced ceramic materials are required to meet increasing high temperature demands of components in advanced propulsion engines for high performance aircraft as well as increasing structural demands in ceramic-composite armor. Monitoring the structural performance of these advanced ceramic materials presents challenges. Recently a new technology, Evisive ScanTM, based on microwave interferometry has been developed that allows condition monitoring. The internationally patented Evisive Scan™ method (1, 2, 3, 4, 5, 6), utilizes microwaves to interrogate dielectric materials. The microwaves are reflected at areas of changing dielectric constant. The reflected energy and the interrogating beam are combined to form an interference pattern which is measured in the transceiver as a signal voltage. The signal voltage is sampled at many positions in the inspection area. This point cloud is displayed as an Evisive Scan™ image, which presents volumetric detail of the inspected part. Over the past two years the technology has been demonstrated on Ceramic Matrix Composites and has shown to be an efficient measurement of porosity and manufacturing defects. The method has also been demonstrated to be applicable to ceramic composite armor made of monolithic ceramic tiles in complex, multilayer structures.
Aerogel Catalysts
Authors: Pierre Alain C.
Published: October 2010

Aerogels are often largely mesoporous solids, with a porosity which may exceed 90 vol%
and a specific surface area up to 1000 m2 g-1. Such materials were first obtained by Kistler in 1932,
and designate gels in which the liquid was replaced with a gas without collapsing the gel solid
network. Contrary to xerogels dried from wet gels by evaporation with an important shrinkage, the
first aerogels were obtained by a “supercritical drying” technique in which the liquid which
impregnated the gels was evacuated after being transformed to a supercritical fluid. The diversity in
nature of the solid constituting the rigid network is very large. It includes simple oxides, multi
oxide compositions, organic and hybrid organic-inorganic polymers and carbon. This diversity as
well as the high specific pore volume and surface area make aerogels applicable either as catalysts
or as catalyst supports. Besides, molecular catalysts such as transition metal complexes or enzymes
can easily be immobilized in aerogels, which opened the road to new supported molecular catalysts
and biocatalysts. This communication reviews the synthesis and properties of oxide aerogel
catalysts.
Creep Behavior of Yb-Doped Barium Cerate Perovskite
Authors: Vaquero-Aguilar Cristina , Jiménez Melendo Manuel
Published: October 2010

Polycrystalline ytterbium-doped barium cerate with composition BaCe0.95Yb0.05O3- has been fabricated by solid state reaction. The compound has an orthorhombic perovskite structure and a fine and homogeneous grain size distribution, with a mean value of 0.4 m. The creep behavior was studied by means of constant crosshead-speed compression tests in air at temperatures of up to 1300 °C. At the lower strain rates and higher temperatures, the material deformed by grain boundary sliding; the corresponding true stress-true strain curves displayed an initial strength drop followed by an extended steady state stage. A continuous transition towards a brittle regime was observed with increasing initial strain rate and/or decreasing temperature.
Photocatalytic Efficiency of ZnO/TiO2 Composite Plates in Degradation of RR180 Dye Solutions
Authors: Konyar Mehmet , Ovali Didem , Yatmaz Huseyn Cengiz , Duran Cihangir , Öztürk Koray
Published: October 2010

Tape casting method was used to prepare ZnO/TiO2 composite plates for photocatalytic
degradation of Reactive Red 180 (RR 180) textile dyes in aqueous solutions. TiO2 content of the
plates was selected as 20 mol%. The final sintering temperature of the plates is 700°C. The
sintering temperature of 700°C was selected to obtain relatively high surface area of the plates
which enhances the photocatalytic activity in the degradation processes. The plates were
characterized by using TG-DTA, BET, XRD and SEM. The efficiencies of the composite plates
during the degradation of the RR180 dye were determined using the laboratory-scale quartz
photoreactor under UVA light irradiation. Over 97% color removal efficiency was obtained in
150min process time for the dye solution at 50 mg/L concentration. Efficient reuse of plates
indicated that the successful photocatalytic degradation was maintained after three consecutive runs.
The addition of TiO2 is found to increase the photocatalytic activity of the ZnO plates in
degradation of the selected dye from water, however, the pure ZnO plates sintered at the same
temperature yielded less color removal efficiency for the same dye solution.
Etch Rate and Dimensional Accuracy of Machinable Glass Ceramics in Chemical Etching
Authors: Ting Huey Tze , Abou-El-Hossein Khaled A. , Chua Han Bing
Published: October 2010

Machinable glass ceramic (MGC) is well known in the micro-electromechanical system and semiconductor industry. Chemical etching is used in this experiment to study the performance of MGC. The etching rate of MGC and its accuracy by indentation method is studied. The categoric parameter applied here is the type of chemical etchant used: hydrochloric (HCl), hydrophosphoric (H3PO4) and hydrobromic (HBr) acids; and, numerical parameters are etching temperature and etching solution. The experimental investigation that was carried out is governed by design of experiment (DoE).
Solid Oxide Electrolyte Based Oxygen Pump
Authors: Spirin Alexey , Lipilin Alexandr , Ivanov Victor , Paranin Sergey , Nikonov Alexey , Khrustov Vladimir , Portnov Dmitriy , Gavrilov Nikolai , Mamaev Alexander
Published: October 2010

The method of electrochemical extraction of oxygen from air employing a solid oxide
electrolyte (SOE) is presented. The prototype of electrochemical oxygen generator (pump) for
medical applications has been developed and fabricated. It is based on thin-walled tubular segments
of YSZ electrolyte (170 μm) with LSM based electrodes (~20 μm). Different technologies:
nanopowder production by laser ablation, casting of polymer-ceramic tapes, formation of
electrodes-electrolyte green structures by radial magnetic pulsed compaction followed by cosintering
at 1200°C, were used for segments fabrication. The magnetron sputtering method was
applied to protect metallic interconnects (Crofer 22 APU) with (Mn-Co)3O4 layer. Presented
oxygen generator prototype produced 9 liters of pure oxygen per hour under applied power of 50 W
at 800°C. No noble metals were used in construction.
Boron Nitride (BN) and Boron Nitride Composites for Applications under Extreme Conditions
Authors: Eichler Jens , Uibel Krishna , Lesniak Christoph
Published: October 2010

Hexagonal boron nitride (h-BN) is a very versatile material that is used in a number of
applications due to its unique combination of properties. This paper reviews typical h-BN qualities
and their applications as functional particle in coatings and as sintered parts. As an example, the
EKamold® coating family is presented in detail for a variety of substrate types and applications.
Furthermore a general overview is given of the effect of the binder phase for hot-pressed h-BN
qualities. And finally the use of h-BN as a composite with a) zirconium oxide for side dams in steel
thin-strip casting and b) with titanium diboride as evaporation boats is described in more detail.
Silicon Nitride Ceramics for Product and Process Innovations
Authors: Berroth Karl
Published: October 2010

During the last years large efforts were made, to get able to supply large and complex components
made of gas pressure sintered silicon nitride. This opened new applications for such ceramic
materials in ambient and very harsh environment and generated new markets for ceramic producers.
The paper presents, a newly developed rapid prototyping routine for complex components as well as
the properties of corresponding materials. Components for innovative avionic and space
applications, dynamic materials testing, liquid metal processing, metal forming and mechanical
engineering are shown. Not only unique properties of the material itself, but also newly developed
and adopted shaping and machining technologies for this specific ceramics have let to highly valued
products.
Due to its very specific set of material properties, silicon nitride has gained a lot of interest. New
approaches in technical equipment were undertaken with corresponding research. However, except
of seals, bearings and cutting tools, none of all expected high volume applications is industrialized.
On the other side, a lot of less spectacular applications are state of the art today. They have opened a
wide field for niche products and lead to technical solutions with less wear and corrosion but
improved products.
Slurry Coating of Environmental Barrier Coating (EBC) on Silicon Carbide Based Material
Authors: Bezzi Federica , Fabbri Paride , Brentari Alida , Mingazzini Claudio , Burresi Emiliano , Beaulardi Leandro , Sangiorgi Sergio
Published: October 2010

In order to increase the component lifetime of SiC based materials in combustion environments, environmental barrier coatings (EBCs) based on ceramic oxides are used to improve corrosion resistance of SiC, due to their high chemical stability. In this work, mullite and barium-strontium-aluminosilicate (BSAS) coatings were deposited by slurry dip coating on SiC substrates. Slurries were prepared by suspending commercial powders in water or ethanol, using appropriate dispersants. Substrates were dipped into the slurry and subsequently dried and heat treated at high temperature to promote densification. SEM observations were carried out to investigate the microstructure of the obtained coatings and to evaluate crack formation, porosity and adhesion.
Ti–Si–C Films Formed by Dual Beam Ion Assisted Deposition
Authors: Twardowska Agnieszka , Rajchel Bogusław , Jaworska Lucyna
Published: October 2010

Ti–Si–C coatings were formed at room temperature on AISI 316L steel substrates by dual beam ion
assisted deposition technique from single compound Ti3SiC2 target. Scanning and transmission
electron microcopy method were used to examine as-deposited coatings. Their morphology was
smooth and dense and their thickness were in the range from 100 nm to 1μm. Raman spectra of
coated substrates were collected up with five peaks at the same positions as for Ti3SiC2 compound
target. TEM and HRTEM examinations, accompanied by SAED analyses revealed that deposited
films were amorphous. Nanoindentation tests were provided on coated and uncoated substrates and
hardness HIT and reduced elastic modulus EIT were calculated using the Oliver & Pharr method.
Effect of Phases on the Frictional Properties of Electroless Ni-B Nano-Composite Coating
Authors: Pal Soupitak , Jayaram Vikram , Biswas Sanjay Kumar , Riddle Yancy
Published: October 2010

As-deposited amorphous (determined through XRD) electroless Ni-B coating upon heat treatment
transforms to crystalline phases, Ni3B, Ni2B and Ni whose volume fractions can vary widely. A
micro and nano tribological study through ball-on-disk tribometer and lateral force microscopy has
been performed to understand the effect of phase mixture (Ni3B +Ni2B) on the frictional properties
of this coating. Though scaling of the contact area from micro to nano level strongly influences the
friction coefficient, it has also been found that increase in the Ni2B:Ni3B ratio of the crystalline
coating reduces the friction coefficient significantly.
Advances in the Field of New Smart Thermal Barrier Coatings
Authors: Pin Lisa , Ansart Florence , Fenech Justine , Lours Philippe , Bonino Jean Pierre , Sniezewski Julien , Le Maoult Yannick
Published: October 2010

This paper deals with the development of a new synthesis technique for functional materials such as Yttria Stabilized Zirconia (YSZ) in the field of thermal barrier coatings. Currently, Thermal Barrier Coatings (TBCs) are manufactured by dry route technologies (EB-PVD or plasma spray) but such methods are directional and often require costly investments and complex operations. For these applications, the sol-gel route, a non directional method, is developed, to process, by suitable chemical modifications, nanocrystalline materials with a controlled morphology. The main advantage of this method is to decrease the crystallization temperature, much lower than the conventional processes, allowing the synthesis of reactive substituted zirconia powders with nanometric particles size. In this study, several suitable architectures for thermal barrier coatings have been achieved in order to show that this process is appropriate for repairing damaged TBC compared to conventional processes. The next step is to investigate spallation mechanisms and overall TBC durability by cyclic oxidation. Preliminary results are promising and research will be develop further to optimize both processing and cyclic oxidation behavior.
Application of SEM/TEM to Tests on Pt Distribution in Al2O3 Films Obtained by Oxidising FeCrAl Steel Foil Coated with Pt-Al Nanofilms
Authors: Reszka Kazimierz , Rakoczy Jan , Morgiel Jerzy
Published: October 2010

Good dispersion of active catalytic elements, their uniform distribution on the carrier’s surface and
availability for neutralised combustion gases are key factors that determine the usability of catalyst
cartridges for automotive catalytic reactors. By examining the morphology of oxide films, with
SEM/STEM method, obtained by oxidation of foil coated with Pt/Al two-layered system (like
laminate), where an Al nanofilm is situated between steel foil and a Pt nanofilm, one can observe
forked and plate whiskers growing directly of substrate. Oxide films obtained from Pt+Al
composite nanofilms were formed differently (where components are intermixed). These films are
marked by chaotic, mutually penetrating fine equiaxed solids and whiskers. In case of composite
nanofilms the grain system obtained in the course of deposition contributed to good Pt grain
refining, and due to that mostly particles from 3 to 9 nm in conventional diameter were formed.
Direct contact between Pt particles and Al particles caused the partial occlusion of Pt particles with
oxide in the process of Al oxidation to be effected.
Effect of Methane Flow Rate on the Microstructural and Mechanical Properties of Silicon Carbide Thin Films Deposited by Reactive DC Magnetron Sputtering
Authors: Baskurt Erdem , Tavşanoğlu Tolga , Onüralp Yücel
Published: October 2010

SiC films were deposited by reactive DC magnetron sputtering of high purity (99.999%) Si target. 3 types of substrates, AISI M2 grade high speed steel, glass and Si (100) wafer were used in each deposition. The effect of different CH4 flow rates on the microstructural properties and surface morphologies were characterized by cross-sectional FE-SEM (Field-Emission Scanning Electron Microscope) observations. SIMS (Secondary Ion Mass Spectrometer) depth profile analysis showed that the elemental film composition was constant over the whole film depth. XRD (X-Ray Diffraction) results indicated that films were amorphous. Nanomechanical properties of SiC films were also investigated.
Oxidation Behavior of Thermal Barrier Coatings on Copper Substrates
Authors: Schloesser Jana , Bäker Martin , Rösler Joachim , Pulz Robert
Published: October 2010

In rocket engine combustion chambers, the cooling channels experience extremely high temperatures and environmental attack. Thermal protection can be provided by Thermal Barrier Coatings. Due to the need of good heat conduction, the inner combustion liner is made of copper. The performance of a standard coating system for nickel based substrates is investigated on copper substrates.
Thermal cycling experiments are performed on the coated samples. Due to temperature limitations of the copper substrate material, no thermally grown oxide forms at the interface of the thermal barrier coating and the bond coat. Delamination of the coatings occurs at the interface between the substrate and the bond coat due to oxide formation of the copper at uncoated edges. In real service a totally dense coating can probably not be assured which is the reason why this failure mode is of importance. Different parameters are used for thermal cycling to understand the underlying mechanisms of delamination. Furthermore, laser heating experiments account for the high thermal gradient in real service. Pilot tests which led to a delamination of the coating at the substrate interface were performed successfully.
Overview: How to Quantify the Capability of Yttrium Silicates to be Used as an Environmental Barrier Coating
Authors: Courcot Emilie , Rebillat Francis
Published: October 2010

To be used as environmental barrier coatings, yttrium silicates must be thermally and
chemically stable at high temperatures, under high pressures in a moist environment. This work
proposes a full method to quantify their thermo chemical and mechanical stabilities: (i) in a
corrosive environment at high temperature and (ii) against the covered material to protect.
These stabilities were first estimated by thermodynamic calculations and further confirmed with
corrosion tests. This first step needed: (i) to measure the partial pressures of yttrium hydroxides
through corrosion tests on the simple oxide, Y2O3 and (ii) to extract the free energies of formation
of gaseous yttrium-hydroxides formed. In a second step, the measured values of coefficients of
thermal expansion (CTE) on these materials allowed identifying what compositions should be
preferentially used, to get CTE close to that of the substrate material to prevent delaminating or
cracking due to CTE mismatch stress. Finally, these materials are deposited on SiC/SiC composites
by plasma spraying. The impact of the morphology, crystallinity, porosity and composition of
elaborated coatings on their corrosion behaviour is highlighted.
Influence of Inorganic Sealant in Hot and Cold Erosive Wear in Plasma Sprayed Alumina Coating
Authors: Vicenzi Juliane , Takimi Antonio S. , Fonseca Ricardo B. , Locatelli Andrei , Malfatti Célia Fraga , Bergmann Carlos Pérez
Published: October 2010

Plasma sprayed alumina coating is applied in many industrial applications in order to promote wear and corrosion resistance. Nonetheless, high porosity remained after deposition is a critical factor because it decreases the wear resistance. Some inorganic sealants can be used to reduce the open pores and superficial micro-cracks effect, improving the wear and corrosion resistance of alumina coatings. In this work, plasma sprayed alumina coating samples were divided into two groups: i) impregnated with inorganic sealant (AlPO4) and heat treated; ii) as deposited. Erosive wear tests were carried out in an erosion rig according to ASTM G76. The samples were subjected to an erodent flux, with impact angles of 30º up to 90º, at a velocity of 50m/s and temperatures of 25°C up to 400°C. The samples were characterized by SEM, Vickers microhardness, potentiodynamic anodic polarization and erosive wear rate. Results showed that erosive wear rate of alumina impregnated coating is lower than without the sealant. The sealed alumina coating presented higher mechanical properties; improved microstructural characteristics and the sealant promoted better lamellae contact, as can be observed by less sharpness in pits formation of microstructure.
Magnetic Properties and High Frequency Response of Single-Phase Z-Type Strontium Cobalt Hexaferrite Prepared by Polymerizable Complex Method
Authors: Kikuchi Takeyuki , Nakamura T. , Yamasaki T. , Nakanishi M. , Fujii T. , Takada J. , Ikeda Y.
Published: October 2010

Single-phase Z-type strontium cobalt hexaferrite was prepared by polymerizable complex
method. Magnetic properties and dynamic magnetic response for high frequency of the Z-type
ferrite were studied. Single-phase Z-type hexaferrite was obtained by heating at 1473K for 5 hours
in air. Phase identification and determination of lattice parameters were carried out by powder
X-ray diffraction (XRD). Magnetic properties were discussed by measuring of M-H curve with
vibrating sample magnetometer (VSM). The complex permeability and permittivity over
0.2-18GHz were measured using a vector network analyzer with transmission-reflection-line (TRL)
calibration. The results show that the single-phase Z-type strontium cobalt hexaferrite prepared in
this study is one of potential candidates for use as electromagnetic wave absorbing materials in the
frequency range 1-3GHz (for hand-held cellular phone and wireless LAN).
In Situ Measurement of Phase Transition of Layered Perovskite BaLn2Mn2O7
Authors: Nakano Hiromi , Ishizawa Nobuo , Sato Hirohisa , Kamegashira Naoki
Published: October 2010

The BaLn2Mn2O7 (Ln = rare earth) has a Sr3Ti2O7-type structure with double block oxygen octahedra belonging to the Ruddlesden-Popper-Type homologous series AO(ABO3)2.
In-situ measurement of the phase transition for BaLn2Mn2O7 was performed using single-crystal X-ray diffraction and a high-temperature transmission electron microscope (TEM). Two types of transitions were observed in BaPr2Mn2O7: the transition from primitive tetragonal (P42/mnm) to body-centered tetragonal (I4/mmm) at around 400 K and the first-order phase transition at around 1040 K. Multiple phase transitions were also observed in BaEu2Mn2O7, with one from P42/mnm to I4/mmm at around 400 K and another, above 550 K, as a first-order phase transition. The high-temperature phase had a 1.5% lattice mismatch along the c-axis compared with the low-temperature phase. We succeeded in recording for the first time in-situ structural change in BaGd2Mn2O7 as a movie by high-temperature TEM. The high-temperature phase nucleated parallel to the (00l) plane as a layer above 550 K and grew until covering the entire inspected region at around 1023 K. The first-order phase transition was caused by the structural and/or electrical distortion of the layered perovskite structure composed of Jahn-Teller ion Mn3+.
Simplified Method of Measuring Magnetic Permeability Temperature Profile for RF Device Applications
Authors: Kuramoto Atsushi , Aoyama Takanobu , Kanie Tomohiko , Noro Yuichi , Takeo Takashi
Published: October 2010

Ferrite is popular as a core material for RF transformers. Since transmission
characteristics of RF transformers are affected by the core’s permeability, which has a large
temperature dependence, the development of a method for measuring the core permeability
temperature profile is important. In this study, a temperature profile measurement of ferrite core
permeability has been investigated using a microstrip line method which has the advantage of the
circuit being compact in size and therefore suitable for measuring temperature profiles. Based on
the results measured with a sample ferrite core, the temperature dependence of RF transformer
performance (isolation) is also discussed. Furthermore, basic results of experiments to compensate
for the degradation in isolation is presented.
Magnetic Properties of Cobalt and Manganese Oxide Spinel Ceramics
Authors: Guillemet-Fritsch Sophie , Tenailleau Christophe , Bordeneuve Helene , Rousset Abel
Published: October 2010

Magnetic susceptibility measurements, magnetization and neutron diffraction results at low temperature for cobalt and manganese oxide spinel ceramics are presented. The Curie temperature varies similarly with the sample composition in ceramics and powders. The experimental molar Curie constant variation is explained by the presence of Co2+, CoIII, Mn3+ and Mn4+, and possibly Co3+ in the octahedral sites for the cobalt rich phases. The magnetic moments of the cations in tetrahedral and octahedral sites are not collinear and the global magnetization is oriented in a third direction.
Spin Flexoelectricity and New Aspects of Micromagnetism
Authors: Pyatakov Alexander P. , Zvezdin Anatoly K. , Sechin D.A. , Sergeev A.S. , Nikolaeva E.P. , Nikolaev A.V. , Logginov Alexander S.
Published: October 2010

The coupling between the strain gradient and electric polarization is known as
flexoelectricity in dielectrics materials. In case of magnetic media it takes the form of electric
polarization induced by spin modulation and vice versa. This spin flexoelectricity causes new
physical phenomena of micromagnetism such as electric field driven magnetic domain wall motion
and electrical control of magnetic vortices in magnets as well as clamping of the magnetic domain
walls at the ferroelectric ones in multiferroics.
Microstructure, Magnetic and Dielectric Properties of CoFe2O4–Pb(Fe1/2Ta1/2)O3-PbTiO3 Composites
Authors: Kulawik Jan , Guzdek Piotr , Szwagierczak Dorota
Published: October 2010

The paper reports on bulk and layered multiferroic composites based on cobalt ferrite and lead iron tantalate-lead titanate solid solution. Syntheses of CoFe2O4 and Pb(Fe1/2Ta1/2)O3 were performed by conventional solid state reactions. 0.5CoFe2O4–0.425Pb(Fe1/2Ta1/2)O3-0.075PbTiO3 bulk composites were prepared by sintering at 900°C. Multilayer composites were fabricated by tape casting, stacking and lamination of alternate ferrite and relaxor layers, followed by cosintering at 950°C. X-ray diffraction analysis and scanning electron microscopic observations confirm that the obtained ceramic samples are composed of ferrite spinel and relaxor perovskite phases. Impedance spectroscopic studies carried out in the temperature range 218-623 K at frequencies 10 Hz–2 MHz show high and broad maxima of dielectric permittivity. On the basis of investigations of magnetization versus magnetic field (up to 85 kOe) and temperature (4-400 K), the behavior typical of hard magnetic materials was found for CF-PFT-PT composites. The measurements carried out at room temperature as a function of the external dc magnetic field and frequency of the sinusoidal ac modulation field, reveal a distinct magnetoelectric effect of the investigated bulk and layered composites.
Synthesis of Bi6Fe2Ti3O18 Aurivillius Phase by Wet Chemical Methods
Authors: Zientara Dariusz , Bućko Mirosław M. , Polnar Joanna
Published: October 2010

The Aurivillius phases in the Bi-Fe-Ti-O system showing multiferroic properties arouse an increasing interest due to their wide potential applications in electronics. These compounds were usually prepared by high temperature solid-state reaction method using respective oxide powders mixed in required stoichiometry. An excess of bismuth oxide was often added due to its evaporation during heat treatment. The mixture of the oxide powders were calcined in air between 700 and 900°C for several or even for several dozen hours. In the present paper the Bi6Fe2Ti3O18 Aurivillius phase was prepared by direct solid state reaction between respective oxides and by co-precipitation – calcination method. Mixture of the oxides and co-precipitated gels were calcined at different temperatures and X-ray diffraction analysis was used for identification of phase composition of the products.
Spin Manipulation in Co-Doped ZnO
Authors: Schmidt Heidemarie
Published: October 2010

The magnetoresistance of n-type conducting, paramagnetic Co-doped ZnO films prepared by pulsed laser deposition on sapphire substrates has been studied experimentally and theoretically. Positive magnetoresistance (MR) of 124% has been observed in the film with the lowest electron concentration of 8.3·1017 cm−3, while only a negative MR of −1.9% was observed in the film with an electron concentration of 9.9·1019 cm−3 at 5 K. The positive MR is attributed to the quantum correction on the conductivity due to the s-d exchange interaction induced spin splitting of the conduction band. The negative MR is attributed to the magnetic field suppressed weak localization [1]. Voltage control of the electron concentration in Schottky diodes revealed a drastic change of the magnetoresistance and demonstrated the electrically controllable magnetotransport behavior in Co-doped ZnO [2]. The magnetically controllable spin polarization in Co-doped ZnO has been demonstrated at 5 K in magnetic tunnel junctions with Co-doped ZnO as a bottom electrode and Co as a top electrode [3]. There spin-polarized electrons were injected from Co-doped ZnO to a crystallized Al2O3 layer and tunnelled through an amorphous Al2O3 barrier. Our studies demonstrate the spin polarization and manipulation in Co-doped ZnO.
Electrical and Magnetic Properties of Polycrystalline Mn-Doped BaTiO3 Thin Films Grown on Pt/Sapphire Substrates by Pulsed Laser Deposition
Authors: Shuai Yao , Zhou Sheng Qiang , Schmidt Heidemarie
Published: October 2010

5 at.% Mn-doped and undoped, 200 nm thick BaTiO3 thin films have been grown under different oxygen partial pressures by pulsed laser deposition on Pt/sapphire substrates. X-ray diffraction (XRD) measurements reveal the same polycrystalline single-phase perovskite structure for all the thin films despite the different oxygen partial pressure, while their preferred orientation strongly depends on the oxygen partial pressure. The 5 at. % Mn-doping decreases the dielectric loss of the Mn-doped BaTiO3 thin films, however, their relative permittivity is also decreased. Ferroelectricity has been probed on the Mn-doped and undoped BaTiO3 thin films grown under relatively high oxygen partial pressure. A ferromagnetic coupling of the Mn dopant ions has been probed at room tempetature on the Mn-doped BaTiO3 thin films prepared under low oxygen partial pressure and is understood in terms of the bound magnetic polaron model.
Influence of the Annealing on the Thermal Stability of Ge-Sb-Te Materials for Recording Devices
Authors: Kozyukhin Sergey , Sherchenkov Alexey A.
Published: October 2010

Phase change memory materials of Ge-Sb-Te system [(GeTe)m(Sb2Te3)n (m : n = 1:1; 1:2; 2:1)] were studied during thermal cycling by differential scanning calorimetry, and thermal properties were determined. Reproducible endothermic peak in the range of 390-415°C was revealed in Ge2Sb2Te5, GeSb2Te4, GeSb4Te7, which may possibly influence on the kinetics and endurance of data reading processes in phase-change memory devices. The nature of this endothermic peak is discussed. It was shown that additional annealing of synthesized Ge2Sb2Te5 increase stability of structure and thermal properties of the material.
Fractal Geometry and Properties of Doped BaTiO3 Ceramics
Authors: Mitic V.V. , Pavlovic V.B. , Kocic L. , Paunovic V. , Zivkovic L.
Published: October 2010

Taking into account that the complex grain structure is difficult to describe by using traditional analytical methods, in this study, in order to establish ceramic grain shapes of sintered BaTiO3, new approach on correlation between microstructure and properties of doped BaTiO3 ceramics based on fractal geometry has been developed. BaTiO3 ceramics doped with various dopants (MnCO3, Er2O3, Yb2O3) were prepared using conventional solid state procedure, and were sintered at 1350oC for four hours.
The microstructure of sintered specimens was investigated by SEM-5300. Using method of fractal modeling a reconstruction of microstructure configurations, like grains shapes, or intergranular contacts has been successfully done. Furthermore, the area of grains surface was calculated using fractal correction that expresses the irregularity of grains surface through fractal dimension. The presented results, indicate that fractal method for ceramics structure analysis provides a new approach for describing, predicting and modeling the grain shape and relations between the BaTiO3-ceramic structure and dielectrical properties.
Integrated ZnO Film Based Acoustic Wave Microfluidics and Biosensors
Authors: Luo Jack K. , Fu Y.Q. , Ashley Greg , Milne Williams I.
Published: October 2010

Lab-on-a-chip (LOC) is one of the most important microsystems with promising applications in microanalysis, drug development and diagnosis, etc. We have been developing a LOC biodetection system using acoustic wave as a single actuation mechanism for both microfluidics and biosensing using low cost piezoelectric ZnO film. Surface acoustic waves (SAW) coupled into the liquid will induce acoustic streaming, or move the droplet on the surface. These have been utilized to make SAW-based micropumps and micromixers which are simple in structure, easy to fabricate, low cost, reliable and efficient. SAW devices and thin film bulk acoustic resonators (FBAR) have been fabricated on nanocrystalline ZnO thin films deposited using sputtering on Si substrates. A streaming velocity up to ~5cm/s within a microdroplet and a droplet moving speed of ~1cm/s have been achieved. SAW based droplet ejection and vaporization have also been realized. SAW devices and FBARs have been used to detect antibody/antigen and rabbit/goat immunoglobulin type G molecules, showing their high sensitivity. The results have demonstrated the feasibility of using a single actuation mechanism for the LOC.
Piezoelectric Thin Film Devices
Authors: Muralt Paul
Published: October 2010

The field of piezoelectric thin films for micro and nano systems combines an exciting
richness of potential applications with many attractive scientific topics on materials processing and
physical properties. Piezoelectricity transforms a mechanical stimulus into an electrical signal, or
electrical energy. Miniature thin film devices detect and measure vibrations and acoustic waves, as
well as generate electrical power in the mW range by the harvesting of vibration energy. An
electrical stimulus can be applied to generate acoustic waves, to damp actively vibrations detected
by the same film, or to drive a micro robot. The ability to act in both directions of transfer between
mechanical and electrical energy allows for high-performing filters, oscillators, and gravimetric
sensors working at frequencies up to10 to 20 GHz. While rigid piezoelectric thin films like AlN
excel in GHz applications such as RF filters, ferroelectric thin films like Pb(Zr,Ti)O3 are more
efficient in energy conversion and include as further dimension a programmable polarity, which is
useful for memory applications.
Fe3O4 Epitaxial Thin Films and Heterostructures: Magnetotransport and Magnetic Properties
Authors: Orna Julia , Morellón Luis , Algarabel Pedro , De Teresa José M. , Fernández-Pacheco Amalio , Simón Gala , Magen Cesar , Pardo José A. , Ibarra M. Ricardo
Published: October 2010

In this article, we review our recent research on Fe3O4 epitaxial thin films and
Fe3O4/MgO/Fe epitaxial heterostructures. More specifically, we report on the magnetotransport
properties of Fe3O4 epitaxial films in a wide range of film thicknesses and temperatures, focusing
on the anomalous, planar and ordinary Hall effects. We also summarize our insight on the origin of
the enhanced magnetic moment found in ultra-thin magnetite films (thickness t < 5 nm). Finally,
our work on the growth, and structural and magnetic characterization of heteroepitaxial
Fe3O4/MgO/Fe trilayers is presented.
Oriented Barium Hexaferrite Thick Films Prepared by Electrophoretic Deposition in a Magnetic Field
Authors: Ovtar Simona , Lisjak Darja , Drofenik Miha
Published: October 2010

Stable suspensions of nanosized barium hexaferrite particles were prepared with the
addition of surfactants. Hydrothermally prepared particles with sizes from 5 to 20 nm and
commercial particles with sizes from 10 to 160 nm were used. The films with thicknesses from 1.5
to 9.5 μm were prepared with electrophoretic deposition in an external magnetic field. The
orientation of the grains in the films was due to the magneto-crystalline anisotropy of the barium
hexaferrite and was determined with X-ray diffraction analysis, scanning electron microscopy and
magnetic measurements. The highest degree of orientation in the films with anisotropic magnetic
behaviour was 90 %.
Magnetoelectric Coupling in Multi-Ferro Fe-Pd/PZT/Fe-Pd Laminate Composites
Authors: Okazaki Teiko , Furuya Yasubumi , Sado Yusuke , Hayashi Yoshiyuki , Sato Syunsuke , Saito Chihiro
Published: October 2010

Magnetoelectric(ME) coupling in multi-ferroic composite designed by using two material
elements of Pb(Zr, Ti)O3 (PZT: 260μm) and magnetostrictive alloys(Galfenol based Fe-Ga-X(X=Al,
Co), ferromagnetic shape memory Fe-Pd) was investigated. Output ME Voltage under the driving
a.c.magnetic field Hac at f = 1 Hz in Fe81Ga19/PZT/ Fe81Ga19, Fe80Ga15Al5 /PZT/ Fe80Ga15Al5,
Fe76Ga17Co7/PZT/ Fe76Ga17Co7 composites, in which the magnetostrictive foils(50μm thickness)
were prepared by rapid solidification, increased in proportion to the actuated force than the
magnetostriction.Moreover，output ME Voltage in Fe70Pd30 / PZT/ Fe70Pd30 laminates, in which the
Fe70Pd30 films (10μm thickness) on PZT were deposited by sputtering method, exhibited 8 V at Hac
of 175Oe, which is larger than 7.16 V for Fe76Ga17Co7 (50μm)/PZT/ Fe76Ga17Co7 (50μm)
composites
New Silicate Glass-Ceramic Materials and Composites
Authors: Hotza Dachamir , de Oliveira Antonio Pedro Novaes
Published: October 2010

New silicate glass-ceramic compositions have been investigated due to their interesting chemical, mechanical, thermal, and electrical properties. LZSA glass-ceramics based on -spodumene (Li2O•Al2O3•4-10SiO2) and zircon (ZrSiO4) crystalline phases have shown good chemical resistance, high bending strength as well as high abrasion resistance, when compared with traditional ceramic materials, and coefficient of thermal expansion from 4.6 to 9.110-6 °C-1. These features basically depend on the nature, size and distribution of the formed crystals as well as on the residual glassy phase. The nature of the formed crystalline phases and consequently the final properties can be controlled by modifying the chemical composition of the parent glass and also by adequate selection of the heat-treatment parameters. The classical fabrication of glass-ceramic materials consists on the preparation of monolithic glass components followed by heat treatments for crystallisation. However, this technology requires high investments and can be justified only for large production. A viable alternative could be the production of glass-ceramics processed from glass powders and consolidated by sintering using the same equipments of traditional ceramic plants. This work reports the manufacturing and characterization of glass-ceramic materials and composites processed by pressing, injection moulding, extrusion, casting, replication, and rapid prototyping.
Nano-Structured Glassy and Ceramic Surfaces: Development of "Active" Materials for an Innovative Approach to Building Industry
Authors: Baldi Giovanni , Cioni Andrea , Dami Valentina , Soldi Annalisa , Signorini Arianna
Published: October 2010

In the last years there was an increasing interest of the scientific and technological community in the field of healthy and ecological buildings. Nanotechnology gives a substantial contribution in the development of new advanced materials, environmentally sustainable and safe for the consumers. Due to their multi-functional behaviour, nano-materials are at the basis of a revolutionary technical improvement in buildings: titania nano-structured films are applied on ceramic and glass surfaces increasing drastically the self-cleaning and anti bacterial activity. Substrates with controlled porosity can be designed to obtain anti-pollution surfaces either for external and internal environments, a photo reactor has been developed in our laboratory: a device to assess the photo degradation kinetic of pollutants (NOx and VOC’s) and help customers in the certification of eco-buildings. Surfaces based on nano-silver have been also developed leading to an anti bacterial effect in absence of light meanwhile anti-scratch and zero porosity substrates can be obtained from nano-zirconia and nano-silica suspensions. CERICOL has developed and scaled-up a “green chemistry” synthesis in water or glycols allowing simple industrial applications on different substrates as tiles, glass, plastic, paint, wood and concrete.
Nano-Sized Metal Oxide Modification Applied in Microfiltration Membrane Technology
Authors: Zhou Jian Er , Chang Qi Bing , Wang Yong Qing
Published: October 2010

Membrane surface modification is the important method to decrease membrane fouling.
Recent efforts have been made to develop the hydrophilic modified ceramic membrane with
nano-sized inorganic coating in our research group. In the modified membrane, the nano coating does
not form a separating layer, just distributes uniformly on the surface of the membrane pore wall. It
results in that: (1) if the feed is water, the water flux of the modified membrane is higher than that of
the unmodified one despite the fact that the mean membrane pore size decreases after the
modification; (2) if the feed is oily emulsion, the steady flux is obtained in a short time and keeps in
the following time. The flux is far higher than that of the unmodified one because the hydrophilic
nano coating prevents the cake from forming on the membrane surface. The nano-sized metal oxide
modification application in the membrane technology not only expands the newly research area of the
membrane technology but also makes the modified ceramic membrane have a good perspective
application in the industry. This paper will introduce the development of the modified membrane
with nano inorganic coating and give a clear future research direction.
Innovations and New Trends in Ceramic Tile Decoration
Authors: Moreno Arnaldo , Lázaro Vicente , Mateu Ana , Reig Yolanda
Published: October 2010

The goal of this paper is to review the latest innovations in ceramic tile decorating
techniques, encompassing not only the most widespread techniques, such as inkjet printing, but also
other decoration techniques with a strong potential to provide tile surfaces with new finishes and
enhanced aesthetics, such as physical vapour deposition and laser treatment.
Effect of pH, Molar Ratio of Fuel to Nitrates and Calcination Temperature on the Glycine-Nitrate Synthesis of Nano CoAl2O4
Authors: Jazayeri Seyyed Hamid , Bondioli Federica , Salem Shiva , Allahverdi Ali , Shirvani Mansoor , Ferrari Anna Maria
Published: October 2010

In this research, solution-based combustion synthesis is applied to prepare the spinel
CoAl2O4 pigment from precursor solution of Al(NO3)3
.9H2O, Co(NO3)2
.6H2O and glycine. Effect of
pH values (2.5, 7, 10.5), molar ratio of fuel to metal nitrates in the precursor solutions (1.5, 2) and
subsequent calcination temperature (800, 1000, 1200 °C) on the powder characteristics are
described. Gel formation, morphologies, specific surface area and colour of the powder are
characterized using DTA/TG, XRD, TEM, BET and UV-Vis. The results indicate that the
crystalline spinel CoAl2O4 is formed at all different Gl/(metal nitrates) molar ratios, pH and
temperatures and higher temperature promote the increase of the crystallite size. According to
TEM figures most of the particles calcined at 800 and 1000 °C has sizes less than 50 and 100 nm,
respectively. Corresponding to results of BET experiment, specific surface area has its maximum
values at pH 7 and decreases with increasing of temperature. Finally, colorability test indicates the
complete stability of the synthesized powder in the glass matrix.
Development of New Ceramic Dyes
Authors: Monrós Guillermo , Llusar Mario , García Araceli , Gargori Carina , Galindo Roberto
Published: October 2010

Research on new ceramic dyes is addressed to obtain best pigmenting materials in order to reach higher thermal stability (e.g. for porcelainised stoneware) than classical pigments, higher chemical stability towards the coloured matrix or low toxicity in order to satisfy health and environmental requirements. The earlier developments on the research in new ceramic pigments based on new crystal structures (e.g. perovskite, hexaaluminates, fergusonite, pseudobrookite …), new chromophores (e.g. ruthenium, bismuth and rare earth ions), or new methods of preparation are discussed in this communication.
New Development in the Non Contact Optical Measurement of Thermo-Mechanical Properties of Materials
Authors: Paganelli Mariano , Paganelli Daniele
Published: October 2010

The optical measurement of thermo-mechanical properties allows the sample to be completely free from constraints. This enables the possibility to measure the true change in size or volume of a material during a sintering process. Thanks to the fact that the measure is carried out with no contact in becomes possible to carry out other measurements during the test, like the change in mass. Joining a double beam optical dilatometer and an electronic scale we can measure simultaneously the change in size with a resolution of one part over 100.000 and the change in weight of the specimen, with a resolution of 1 part over 10.000.
Moreover, thanks to a innovative temperature controller design, the heat treatment can be designed with complete freedom, even from a mathematical formula (i.e. sinusoidal or exponential) and it can be controlled by the change in size of the specimen during the test. This makes it possible to perform the controlled rate sintering (shrinkage) even if the driving force of the sintering process is the viscous flow of glassy phases, like in traditional ceramics.
Clay Structural Transformations during Firing
Authors: Blanchart Philippe , Deniel Sarah , Tessier-Doyen Nicolas
Published: October 2010

Silicate ceramics with clays are some of the most complicated ceramic systems
because of the very complex relationship between the behavior of mineral materials during
the ceramic processing and the transformations during heating. A major challenge is to predict
the phase transformations in silicate ceramics, since complex relationship occur between the
microstructural and structural characteristics of fired product and the physical properties.
Clay minerals undergo strong structural transformations during heating, simultaneously to a
complex path of thermal transformations. Individual reactions cannot simply identify since
they are closely related and overlapped. At temperature above 800°C, new phases are
recrystallized and many of the reactions are strongly topotactic.
Mullite is the most important phase, which recrystallizes with a range of morphology and
stoichiometry. Variables affecting the mullite formation include the clay mineral type and
behavior during heating, the possible occurrence of liquid and impurities as Fe. It results in
large variations of the stoichiometry and shape of mullite crystals, which are embedded in a
low ordered phase to form a micro-composite microstructure.
This presentation will review recent research, looking at structural transformations in some
typically used phyllosilicate systems : (i) structural transformation of kaolinite and mica
phases were identified at temperature up to 1100°C. They evidence a residual structural order
of high temperature phases which is favorable to the topotactic recrystallization of mullite; (ii)
from the high temperature form of phyllosilicates, an organized network of mullite can be
obtained; (iii) the composition of a local and transient liquid and the presence of minor
elements as Fe has a significant influence on the mullite morphology; (iv) mechanical
properties are closely related to size and organization degree of the mullite network; (v) the
process itself influence the kinetic of structural transformation and particularly the powder
compact density and the thermal cycle. These research in silicate ceramics evidence multiple
and complex challenges, providing opportunities for future development.