Volume 66

doi: 10.4028/www.scientific.net/AST.66

Paper Title Page

Authors: Vittorio Colombo, Emanuele Ghedini, Paolo Sanibondi
Abstract: Thermal plasma processes play nowadays a key role in many industrial applications, such as powder densification and spheroidization, synthesis of nano-powders, treatment of waste materials and spraying of thin coatings. Although many of these applications have been fully implemented industrially for many decades, modelling plays an important factor in their continued development and improvement. 3-D simulation of the behaviour of commercial inductively coupled (RF) plasma can be useful tool to predict the main features of plasma assisted treating and processing of injected raw materials. The effects of changing coil current frequency, the hydrogen mixing in argon primary gas and the flow patterns and temperature distributions have been investigated. 3-D time-dependent modelling DC non-transferred arc plasma torch for plasma spraying operating at atmospheric pressure can allow the prediction of particle trajectories and thermal history, the analysis of the influence of the plasma jet cold gas entrained eddies on particle behaviour and the mechanisms that can lead to a fluctuating and non homogeneous heating of the particle stream. All computations have been performed using a customized version of the CFD commercial code FLUENT©.
Authors: Agnieszka Twardowska, Bogusław Rajchel, Lucyna Jaworska
Abstract: 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.
Authors: M. Federica de Riccardis, Virginia Martina, Daniela Carbone, Paolo Rotolo, Annapaola Caricato, Gilberto Leggieri, Luciano Pilloni, Leander Tapfer, Rossella Giorgi, Elena Salernitano
Abstract: Poly(etherether-ketone)-alumina coating were deposited by EPD. In order to densify the coatings, conventional thermal treatments were performed at a temperature equal or higher than the melting point of the polymer. The samples treated at the lower temperature showed an increase in the quality of crystallinity of the polymer. As an alternative method, an excimer laser was used to treat the surface of the composite coatings. The laser beam irradiation did not induce any modification in the crystalline structure of the polymer and at the same time did not produce strong degradation of the polymer molecule, also when the laser beam fluence was higher than the ablation limit. The most relevant modification induced by both the treatments was a change in the morphology and the porosity.
Authors: Kazimierz Reszka, Jan Rakoczy, Jerzy Morgiel
Abstract: 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.
Authors: Virginia Martina, M. Federica de Riccardis, Daniela Carbone
Abstract: Poly(etherether-ketone) (PEEK) suspensions in ethanol and isopropanol containing also α-alumina and hydroxyapatite powders were studied. An innovative method was used in the study of the quality of suspensions. We studied suspensions by means of zeta potential and grain-size measurements. The comparison amongst the different suspensions was carried out by using statistical and chemometric tools, especially by the use of an explorative test based on the Principal Component Analysis (PCA). The chemometric analysis was performed by involving different combinations of each type of powder and each type of solvent.
Authors: Erdem Baskurt, Tolga Tavşanoğlu, Yücel Onüralp
Abstract: 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.
Authors: Nutthanun Moolsradoo, Hirohumi Sato, Shuichi Watanabe
Abstract: The element added diamond-like carbon films (hydrogen, fluorine, and sulfur) fabricated from C2H2:H2, C2H2:CF4 and C2H2:SF6 mixtures were used to study the effects of element contents on the spin density (ESR) and their relation to the changes in the structure of the DLC films deposited by PBII and RF-CVD method. The Raman spectroscopy was represented along with the ESR. The results indicate that the ESR spin density and g value of H-DLC, F-DLC, and S-DLC films deposited by PBII method decreases with element addition, attributed to the dangling bond was strongly observed after element addition. The Raman G peak position shifts towards higher, while the ID/IG intensity ratio increases with element addition and changes of bias voltage. For H-DLC films deposited by RF-CVD method, the spin density and g value decreases, the G peak shifts toward higher and ID/IG intensity ratio increases with hydrogen addition, that similar to H-DLC films deposited by PBII method. The ID/IG intensity ratio increases with hydrogen addition, indicating that the number of sp2 graphitic clusters of aromatic rings increases in the structure, and the decrease of spin density is correlated to the increase of the paramagnetic centers in the sp2-bonded graphite-like carbon structures, indicating to the spins originate mainly from the sp2 sites in the graphite-like carbon structures.
Authors: Jiří Matějíček, Pavel Chráska
Abstract: Thermonuclear fusion is a potential source of cleaner and safer energy for the future. Its technological realization depends on the development of materials able to survive and function in extreme conditions, often involving a variety of loading – thermal, mechanical, chemical and irradiation. Single bulk materials are often at the edge of their properties limits; therefore, composites and coatings are intensely studied. This article reviews the development, characteristics and applications of coatings for fusion reactor materials. First, the technological objectives and material-environment interactions are briefly summarized, together with materials requirements and the role of coatings. Then, specific applications in different areas of a fusion device are reviewed, namely the plasma facing components, electrical insulation, diffusion and permeation barriers. Various coating fabrication methods are mentioned and the respective coating characteristics are compared. Selected case studies are presented, with particular focus given to ITER and to ceramic coatings.

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