Search

Passive oxide layer of Al prevents the reaction between aluminum and water. Activation of aluminum powder was performed by hydrogen plasma at pressure of 12 Pa for 5, 15 and 30 minutes. Plasma was generated using DC energy source. SEM views of Al powder do not show any significant changes of the surface. XRD patterns reveal small aluminum hydroxide peaks after plasma activation for 15 and 30 min. Gas analysis shows lower concentration of O, N and H after plasma treatment. Notable hydrogen production was observed after reaction between small amount of Al and alkaline water. [ABSTRACT FROM AUTHOR]

In this study lanthanum niobium oxide thin films with different stoichiometry were deposited using magnetron sputtering method, surface structure was investigated and surface roughness parameters were calculated. It was found that most of the films exhibit small surface formations with an exception of thin films with stoichiometry of 0,98:1 (La:Nb) which exhibit much larger, isolated formations with smooth surface between them. It was determined that thin film stoichiometry infuences surface roughness and growth mechanism of thin films. [ABSTRACT FROM AUTHOR]

This paper reports on an investigation of the morphological and electrical properties of TiO2 materials fabricated by e-beam deposition technique. It was found that substrate temperature has influence on films stability. Film becomes not stable at low substrate temperature due to high residual stresses. The conductivity measurements at different conditions show that TiO2 can be good electrolyte material for solid oxide proton conducting fuel cells. [ABSTRACT FROM AUTHOR]

This paper reports the investigation of structural properties of gadolinium doped ceria oxide (GDC) thin films formed by e-beam deposition technique. It was found that substrate temperature during deposition has influence on the crystallite size and structure. Crystallite size grows up to 77-84 nm with increasing substrate temperature during deposition. The growing texture of the films is changing at a higher than 450°C substrate temperature. [ABSTRACT FROM AUTHOR]

This paper presents the investigation of multilayer thin films microstructure for IT-SOFC's electrolyte. Two the most promising electrolytes materials were chosen - cerium doped by gadolinium (GDC) and samarium (SDC). The GDC-SDC multilayer sandwich system of 1, 2 and 3 layers was studied. The main aim of this work was to find out how interconnections between two materials influence the oxygen ion permeability. [ABSTRACT FROM AUTHOR]

This study aims to examine the partial reduction of TiO2 by ion sputtering. It is shown that room temperature oxidation of thin Ti films under water vapor plasma treatment is limited by reduction processes. The oxidation rate is balanced by the removal rate of oxygen atoms under plasma radiation resulting in the formation of suboxides as well as an oxygen deficient surface in the steady state. In these conditions, the dominant parameters limiting oxidation rate become plasma radiation intensity and plasma activated reduction processes. The phenomenological analysis of dominant processes is presented. [ABSTRACT FROM AUTHOR]

Yttria-stabilized zirconium are most widely used electrolyte for solid oxide fuel cells. In this study YSZ powder with different BET thin films were deposited by e-beam evaporation technique onto optical quartz substrate. Influence of initial powder BET and deposition rate on formed thin film surface roughness and structure were investigated, It was determined that surface roughness is influenced by both initial powder BET and deposition rate of thin films. [ABSTRACT FROM AUTHOR]

Ccria-based thin films are potential materials for use as electrolytes in micro-solid oxide fuel cells. In this study GDC thin ceramic films were deposited by e-beam evaporation of Gd0.10Ce0.90O2 nano powder (particle size 5 ± 10 nm) and the influence of the deposition rate on formed thin films electrical and microstructure properties were studied. The electrical conductivity of nanocrystalline thin ceramics film has been studied as a function of temperature and correlated with microstructure. It was determined that the deposition rate has influence on crystallite size and crystallite size changes from 7.2 to 8.8 nm at different deposition rate. The XRD measurements show that the formed GDC thin films have cubic structure at all deposition rates. [ABSTRACT FROM AUTHOR]

Oxide materials with high proton conductivity (because of their high selectivity of hydrogen) are good candidates for hydrogen separation membranes [1]. One of the candidates for proton conductivity is corundum type chromium oxide thin films [2]. The chromium oxide thin films could be formed by different techniques. The pulsed - DC magnetron sputtering is one of the chromium oxide thin films synthesis techniques, which is versatile and more effective than other magnetron sputtering techniques [3, 4]. The main requirement for chromium oxide thin films used for hydrogen separation is dense microstructure and stoichiometry. The influence of pulsed DC sputtering technological parameters (oxygen partial pressure, the distance between the substrate, and the magnetron cathode) on the properties of formed chromium oxide thin films were investigated in this work. The oxygen pressure was changed form 2 Pa to 16 Pa and the distance of the substrate to the magnetron cathode - from 3 cm to 5 cm. Chromium oxide thin films were characterized by X - ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive X-ray (EDX), and ellipsometer. Thin films of chromium oxide were deposited onto Alloy- 600 (Ni, Cr, Fe, Mo and Co alloy), Hastelloy-X, quartz, and silicon substrates. The formed chromium oxide thin films showed an amorphous structure. The polycrystalline structure was obtained when the distance of the substrate to the magnetron cathode was 3 cm. Cross sections of synthesized chromium oxide thin films show that they grow with columnar structure. [ABSTRACT FROM AUTHOR]

New hydrogen separation technology using nanocrystalline membranes immersed in the ambient of the ionized hydrocarbon gases are discussed. Grain boundaries of nanomaterials doped with impurities are considered as nanochannels for hydrogen separation. The maintenance of the atomically clean membrane surfaces by physical and chemical sputtering processes is considered. [ABSTRACT FROM AUTHOR]

In this paper, attention in focused on the nanostructured magnesium films for hydrogen storage. It is shown that 2 μm thick Mg film is transformed into MgH2 film under high-flux and fluence hydrogen plasma immersion ion implantation at 450 K for 15 mm. All hydrogen desorbs around 530 K temperature, which corresponds to the decomposition of MgH2 -> Mg + H2. The Mg-based hydrides compounds are too stable for practical applications and can be destabilized by adding small amount of transition metals (Ti, V, Ni). The results provide new aspects of hydriding of thin nanocrystalline film materials under highly nonequalibrium conditions on the surface and destabilization oh hydrides using additives. [ABSTRACT FROM AUTHOR]

Titanium oxide (TiO2) thin films (1-4 μm thickness) were deposited on porous Hastelloy-X substrates using pulse dc-magnetron sputtering. Also, for getting higher density thin films, were changed other technological parameters such as bias voltage and oxygen partial pressure, when the discharge power, distance between magnetron and substrate was kept constant (optimal). The optical, structural properties, densification process and porosity of titanium oxide (TiO2) thin films were investigated with XRD, SEM and ellipsometer (632.8 nm). With the decrease of oxygen pressure from 1.3 to 6.0 Pa, deposition rate decreased nearly 15 %. The results show that refractive index changes slightly (from 2.84 to 2.75) with increase of the oxygen partial pressure from 1.3 to 5.9 Pa and formed TiO2 thin films start to be denser. The growth rate of thin films decreases nearly 15 % with adding the bias voltage to the substrate during the deposition. The refractive index changes from 2.80 to 2.51 with increase of bias voltage from 0 to 150 V, and the deposited thin films start to be denser, also. [ABSTRACT FROM AUTHOR]

Samarium doped ceria oxide (SDC) thin films were deposited onto optical quartz (SiO2) and Alloy 600 (Fe-Ni-Cr) substrates by e-beam evaporation of Sm0.15Ce0.85O1.95 nanopowder. The influence of electron gun power and temperature of substrate on film thickness, porosity, refractive index and crystallite size were studied. Properties of deposited films were studied by scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmittance spectroscopy in a visible light wavelength region. It was determined that electron gun power (in range from 0.12 to 0.78 kW) and substrate temperature has influence on crystallite size (increased from 5 to 19.2 nm) and porosity. [ABSTRACT FROM AUTHOR]

Oxide materials with high proton conductivity are good candidates for hydrogen separation membranes. Such membranes have high selectivity for hydrogen separation. One of the candidates for proton conductivity is corundum type chromium oxide. Moreover chromium oxide has catalytically properties, which are useful for splitting hydrocarbons to hydrogen and carbon. The aim of this work is the synthesis of chromium (III) oxide thin films, which can be used as proton membranes. The films were synthesized by thermal annealing of Cr thin films at different temperatures in air. [ABSTRACT FROM AUTHOR]

The behaviors of hydrogen in Mg-Ni thin films on quartz substrate were investigated in this work. The Mg2Ni 1 μm thin films were successfully deposited applying magnetron sputtering techniques. The deposited layers were hydrogenated employing equilibrium technologies in hydrogen atmosphere, at high hydrogen pressure and temperature. There were 8 samples investigated. The first sample was hydrided at 180 °C, and then the temperature was being increased by 10 °C and the last sample was hydrided at 250 °C. Hydrogenation duration of all samples was 1 hour. The XRD results showed that the main phases after hydrogenation were Mg2NiH4 independently of the synthesis temperatures. However, monoclinic low temperature (LT) Mg2NiH4 phase formed when the samples were hydrided below 220 °C respectively, when hydrogenation temperature was over 220 °C, cubic high temperature (HT) Mg2NiH4 phase formed. [ABSTRACT FROM AUTHOR]

In the last decades amorphous metal alloys were under intensive research because of their specific properties. Furthermore amorphous magnetic metallic alloys, also known as metallic glasses, are important (from the point) because of their application, in industry for computers, information technology, recording media and etc [1-3], Fe1-xZrx amorphous films co-condensed by magnetron sputtering were studied. X-ray diffraction methods were applied for studying a glass forming range vs the composition of the elements. Electrical properties of the samples were measured by so-called four-probe and Van der Pouw methods. The surface morphology was investigated by SEM. The results show that amorphous Fe1-xZrx alloys with 1.5 nm crystallites could be synthesized by magnetron co-sputtering on the substrates at room temperature when the alloys composition was Fe0.91Zr0.09 with a very smooth surface. The grain size of alloys decreased increasing Zr concentration. The resistivity of the thin films of these alloys depends on the crystalline size and structure. [ABSTRACT FROM AUTHOR]

Oxide materials with high proton conductivity are! good candidates for hydrogen separation membranes. Such membranes have high selectivity for hydrogen separation. One of the candidates for proton conductivity is corundum type chromium oxide. Moreover chromium oxide has catalytically properties, which are useful for splitting hydrocarbons to hydrogen and carbon. The aim of this work is the synthesis of chromium (III) oxide thin films, which can be used as proton membranes. The films were synthesized by thermal annealing of Cr thin films at different temperatures in air. [ABSTRACT FROM AUTHOR]

The behaviors of hydrogen in Mg-Ni thin films on quartz substrate were investigated in this work. The Mg2Ni 1 μm thin films were successfully deposited applying magnetron sputtering techniques. The deposited layers were hydrogenated employing equilibrium technologies in hydrogen atmosphere, at high hydrogen pressure and temperature. There were 8 samples investigated. The first sample was hydrided at 180 °C, and then the temperature was being increased by 10 °C and the last sample was hydrided at 250 °C. Hydrogenation duration of all samples was 1 hour. The XRD results showed that the main phases after hydrogenation were Mg2NiH4 independently of the synthesis temperatures. However, monoclinic low temperature (LT) Mg2NiH4 phase formed when the samples were hydrided below 220 °C respectively, when hydrogenation temperature was over 220 °C, cubic high temperature (HT) Mg2NiH4 phase formed. [ABSTRACT FROM AUTHOR]

In the last decades amorphous metal alloys were under intensive research because of their specific properties. Furthermore amorphous magnetic metallic alloys, also known as metallic glasses, are important (from the point) because of their application, in industry for computers, information technology, recording media and etc [1-3], Fe1-xZrx amorphous films co-condensed by magnetron sputtering were studied. X-ray diffraction methods were applied for studying a glass forming range vs the composition of the elements. Electrical properties of the samples were measured by so-called four-probe and Van der Pouw methods. The surface morphology was investigated by SEM. The results show that amorphous Fe1-xZrx alloys with 1.5 nm crystallites could be synthesized by magnetron co-sputtering on the substrates at room temperature when the alloys composition was Fe0.91Zr0.09 with a very smooth surface. The grain size of alloys decreased increasing Zr concentration. The resistivity of the thin films of these alloys depends on the crystalline size and structure. [ABSTRACT FROM AUTHOR]

Mirco and nano size carbon structures were deposited on Ni/Si substrates from an argonacetylene gas mixture at a atmospheric pressure using a plasma jet technique. The Ar/C2H2 gas volume ratio was 100:1, 200:1, and 250:1, meanwhile the plasma flow temperature ranking from 800 to 1000 °C. SEM results indicated that on the surface of the substrate treated at 1000 °C, formation of carbon nanotubes of 200-300 nm diameter were found. Raman spectroscopy measurements indicated that the spectra have bands related to carbon nanostructures. [ABSTRACT FROM AUTHOR]

Depleting fossil resources and environmental concerns are raising great interest in renewable energy. Unfortunately, renewable energy sources are not equally available throughout time and require energy storage systems to balance supply and demand. Hydrogen as a way of chemical energy storage has a great potential to solve a whole set of energy related problems. A lot of efforts have been made to find a perfect solid state hydrogen storage material which would have high hydrogen storage capacity, proper thermodynamic properties and good cycling stability [1-3]. However, no single material was able to meet the requirement and it became clear that different sorts of material engineering is needed. Traditionally scientist looked for solutions which would improve the bulk properties of the hydride. The biggest step at improving hydrogen storage by changing their bulk properties was achieved by Bogdanavic when he added titanium chloride to sodium alanate [4-5]. Later it was realised that surface properties of the hydrogen storage materials can be equally important. It was shown that for particular materials hydrogenation kinetics can have a limiting step of H2 dissociation at the surface or diffusion from the surface to the bulk. Various surface catalyst such as Pd, V and Ni significantly increased the hydrogenation kinetics but as with the bulk improvement their effect was not enough to achieve targets set by international energy agencies and industry. During current research it was tested if manipulation of thin film-substrate interaction zone and controlling free surface energy could have significant effects on hydrogenation properties of thin films deposited by magnetron sputtering. For this purpose we have chosen to use a well known and widely described Mg based materials and to deposit them on to the different substrates affected by different plasma treatment. The received experimental data has revealed interesting material behaviour under hydrogenation and provided experimental proof of concept that different surface pretreatment can be used to alter the overall hydrogenation properties of metal hydrides. [ABSTRACT FROM AUTHOR]

To satisfy the growing needs in energy, the tremendous efforts are concentrated to increase the efficiency of the existing energy sources. The environmental problems are driving for the search of the alternative energy sources with small or zero emission of pollutants, such as hydro, wind and solar energy sources. The recent achievements show that hydrogen energetic is one of the most perspective technologies for solution of environmental and energetic problems and is able to change the existing energy sources, such as oil, natural gas, coal, etc. Hydrogen energetic includes different areas of science and industry and mainly consists of hydrogen production from water or hydrocarbons, hydrogen storage in compressed, liquefied or solid storage systems and fuel cells technologies for hydrogen conversion into electricity. The water - nanomaterials reaction approach for hydrogen production with following materials regeneration in plasma leads to new possibilities in hydrogen energetic. This approach based on essential elements: water interaction with active nanomaterials surfaces with following production of hydrogen which can be used in fuel cells for hydrogen conversion into electricity. A nanomaterials surface become non - active during hydrogen production process and becomes reactivated during novel plasma based activation procedure. This approach has potential to solve main hydrogen energetic challenge - hydrogen storage by avoiding it and realizing hydrogen production on - board as we need it. It gives us possibility to realize vision of the car which is fuelled by water. The presentation gives basic understanding and review of preliminary experimental results of interactions between water and nanostructured materials surfaces, regeneration of solid material surfaces in plasma based environment and the use of nanocatalytic particles for hydrogen separation from water. [ABSTRACT FROM AUTHOR]