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Brimbal, D.
Paris XI Univ. (France); DEN-DMN (France)2011
Paris XI Univ. (France); DEN-DMN (France)2011
AbstractAbstract
[en] Ferritic-martensitic steels are excellent potential candidates for a use as structural materials in future fusion reactors. For this application, they will have to withstand high fluxes of 14 MeV neutrons that will create atomic displacement cascades and transmutation reactions which will produce large quantities of helium. In order to understand the basic mechanisms under irradiation with helium, we have studied the effects of helium and those of chromium. Pure iron and a Fe-5.4 wt.% Cr model alloy were irradiated at the JANNuS platform in dual-beam mode with Fe+ and He+ ions and in single-beam mode with Fe+ ions at 500 C. This platform enabled us to follow the evolution of damage up to low doses (1 dpa) and to characterize the microstructure at high doses (100 dpa). It also allowed us to observe in situ irradiation/implantation kinetic effects in a TEM coupled to two accelerators. The nature and distribution of irradiation defects was determined: they are essentially dislocation loops with a<100> Burgers vectors and cavities/bubbles. We have demonstrated that the co-implantation of helium and the addition of chromium both reduce the mobility of dislocation loops. The addition of chromium reduces swelling for all the irradiation conditions studied, with or without helium. In pure iron irradiated with helium, an original phenomenon was discovered for the first time: cavities/bubbles nucleate heterogeneously on the planes of the dislocation loops. We have also interpreted our experimental results in pure iron irradiated with helium using the cluster dynamics code CRESCENDO. (author)
[fr]
Les aciers ferritiques/martensitiques au chrome sont d'excellents materiaux candidats pour les structures des futurs reacteurs de fusion. En conditions de service, ils devront resister a des flux intenses de neutrons de 14 MeV qui creeront des cascades de deplacements atomiques et des produits de transmutation tels que l'helium. Afin de mieux comprendre le comportement de ces materiaux sous irradiation en presence d'helium, nous avons etudie les effets de l'helium et ceux du chrome dans le cadre de ce travail de these. Du fer pur et un alliage modele Fe-5,4%pds Cr ont ainsi ete irradies dans la plateforme JANNuS a 500 C en bi-faisceau avec des ions Fe et He et en mono-faisceau avec des ions Fe+. L'utilisation de cette plateforme a permis de suivre l'evolution du dommage jusqu'a des doses faibles (1 dpa) et de caracteriser la microstructure apres irradiation a forte dose (100 dpa) Elle a egalement permis l'observation in situ dans un MET couple a deux accelerateurs des effets cinetiques d'implantation/irradiation. La nature et la repartition des defauts d'irradiation ont ete determines: ce sont essentiellement des boucles de dislocations de vecteur de Burgers de type a<100> et des cavites/bulles. Nous avons montre que la co-implantation d'helium et l'addition de chrome reduisaient la mobilite des boucles. Par ailleurs, avec ou sans helium, l'addition de chrome reduit le gonflement dans toutes les conditions etudiees. De plus, dans le fer pur irradie avec helium, un phenomene original de germination heterogene de cavites dans les plans des boucles a ete mis en evidence. Enfin, nous avons egalement utilise le code de dynamique d'amas CRESCENDO pour interpreter les resultats experimentaux dans le fer pur irradie avec heliumOriginal Title
Evolution microstructurale du fer pur et d'un alliage Fe-Cr sous irradiation avec injection simultanee d'helium: etude experimentale et modelisation
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2 Dec 2011; 202 p; 136 refs.; Available from the INIS Liaison Officer for France, see the 'INIS contacts' section of the INIS-NKM website for current contact and E-mail addresses: http://www.iaea.org/INIS/contacts/; Physique
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[en] A combined experimental and computational study is performed to investigate the origin and characteristics of the surface features observed in SEM images of thin polymer films deposited in matrix-assisted pulsed laser evaporation (MAPLE). Analysis of high-resolution SEM images of surface morphologies of the films deposited at different fluences reveals that the mass distributions of the surface features can be well described by a power-law, Y(N) ∝ N -t, with exponent -t ∼ -1.6. Molecular dynamic simulations of the MAPLE process predict a similar size distribution for large clusters observed in the ablation plume. A weak dependence of the cluster size distributions on fluence and target composition suggests that the power-law cluster size distribution may be a general characteristic of the ablation plume generated as a result of an explosive decomposition of a target region overheated above the limit of its thermodynamic stability. Based on the simulation results, we suggest that the ejection of large matrix-polymer clusters, followed by evaporation of the volatile matrix, is responsible for the formation of the surface features observed in the polymer films deposited in MAPLE experiments
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5-ICPEPA: 5. international conference on photo-excited processes and applications; Charlottesville, VA (United States); 3-7 Sep 2006; S0169-4332(07)00124-9; Copyright (c) 2007 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
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Gu Qinlin; Cheng Xianhua, E-mail: xhcheng@sjtu.edu.cn2007
AbstractAbstract
[en] Lanthanum-based thin films deposited on the phosphonate 3-aminopropyltriethoxysilane (APTES) self-assembled monolayer (SAM) were prepared on the hydroxylated glass substrate by a self-assembling process from specially formulated solution. Chemical compositions of the films and chemical state of the elements were detected by X-ray photoelectron spectrometry (XPS). The thickness of the films was determined with an ellipsometer, while the morphologies of the original and worn surfaces of the samples were analyzed by means of atomic force microscopy (AFM) and scanning electron microscopy (SEM), respectively. The tribological properties of the films sliding against GCr15 steel ball were evaluated on a UMT-2MT reciprocating friction and wear tester. As the results, the target film was obtained and reaction may have taken place between the film and the glass substrate. The tribological results show that lanthanum-based thin films are superior in reducing friction and resisting wear compared with APTES-SAM and phosphorylated APTES-SAM. SEM observation of the morphologies of worn surfaces indicates that the wear of APTES-SAM and the phosphorylated APTES-SAM is characteristic of brittle fracture and severe abrasion. Differently, slight abrasion and micro-crack dominate the wear of lanthanum-based thin films. The superior friction reduction and wear resistance of lanthanum-based thin films are attributed to the enhanced load-carrying capacity of the inorganic lanthanum particles in the lanthanum-based thin films as well as good adhesion of the films to the substrate
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4. international workshop on basic aspects of nonequilibrium plasmas interacting with surfaces - Negative ions, their function and designability; Lake Kawaguchi (Japan); 30 Jan - 1 Feb 2006; 4. EU-Japan joint symposium on plasma processes; Lake Kawaguchi (Japan); 30 Jan - 1 Feb 2006; S0169-4332(07)00202-4; Copyright (c) 2007 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
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ALLOYS, CARBON ADDITIONS, DIMENSIONS, DISPERSIONS, ELECTRON MICROSCOPY, ELECTRON SPECTROSCOPY, FILMS, HOMOGENEOUS MIXTURES, IRON ALLOYS, IRON BASE ALLOYS, MEASURING INSTRUMENTS, MICROSCOPY, MIXTURES, PHOTOELECTRON SPECTROSCOPY, POLARIMETERS, RARE EARTH COMPOUNDS, SPECTROSCOPY, TRANSITION ELEMENT ALLOYS
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Danish, N.; Garg, M.K.; Rane, R.S.; Jhala, P.B.; Nema, S.K., E-mail: nema@ipr.res.in2007
AbstractAbstract
[en] Dielectric barrier discharge (DBD) of Helium and Helium + air modify the surface of Angora rabbit fibers. DBD treatment carried out at different power densities, changes the morphology and chemical composition of the surface of Angora fiber. Scanning electron microscopy (SEM) results reveal that the DBD treatment eliminates fibrosity from the fiber surface. X-ray photoelectron spectroscopy and Fourier transform infrared spectrometer (FTIR) spectrum confirm the increase in oxygen bonding at the surface. These changes reduce shedding of the fibers and improve dye-uptake property. However, even after 10 min of plasma exposure the thermal insulation (heat keeping ratio) of Angora fibers nearly remain unchanged. It has been noticed that DBD treatment (10 min) reduces whiteness of the fiber
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4. international workshop on basic aspects of nonequilibrium plasmas interacting with surfaces - Negative ions, their function and designability; Lake Kawaguchi (Japan); 30 Jan - 1 Feb 2006; 4. EU-Japan joint symposium on plasma processes; Lake Kawaguchi (Japan); 30 Jan - 1 Feb 2006; S0169-4332(07)00212-7; Copyright (c) 2007 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
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[en] Pt/N-codoped TiO2 nanotubes were prepared and characterized by various analytical methods, such as transmission electron microscope (TEM), diffuse reflection spectra (DRS), X-ray powder diffraction (XRD), X-ray photoelectron emission spectroscopy (XPS) and fluorescence spectra (FL). The photocatalytic efficiency was evaluated by the photodegradation of Rhodamine B (RB) in an aqueous solution under visible light irradiation. It has been confirmed that Pt/N-codoped TiO2 nanotubes could be excited by visible light and the recombination rate of electron-hole pairs declined significantly. The higher visible light activity is due to the codoping of nitrogen and platinum
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S0169-4332(07)00233-4; Copyright (c) 2007 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
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ALLOYS, CATALYSIS, CHALCOGENIDES, COHERENT SCATTERING, DIFFRACTION, DISPERSIONS, ELECTROMAGNETIC RADIATION, ELECTRON MICROSCOPY, ELECTRON SPECTROSCOPY, EMISSION SPECTROSCOPY, HOMOGENEOUS MIXTURES, MATERIALS, MICROSCOPY, MIXTURES, NANOSTRUCTURES, OXIDES, OXYGEN COMPOUNDS, PHOTOELECTRON SPECTROSCOPY, RADIATIONS, SCATTERING, SOLUTIONS, SPECTROSCOPY, TITANIUM COMPOUNDS, TRANSITION ELEMENT COMPOUNDS
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[en] The corrosion products of a TM 23 bronze-leaded alloy (Cu 72%, Pb 15%, Zn 8% and Sn 5%) were obtained in a salt spray cabinet after exposition during 120 h and 1000 h. The products obtained were studied using scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction. The major products of bronze-leaded corrosion were oxides and basic salts of Cu, CuCl2.3Cu(OH)2, and Pb, Pb(OH)Cl. The results can be attributed to a kinetic control of the corrosion reactions
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S0169-4332(07)00272-3; Copyright (c) 2007 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
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[en] Experiments of autogenous laser full penetration welding between dissimilar cast Ni-based superalloy K418 and alloy steel 42CrMo flat plates with 3.5 mm thickness were conducted using a 3 kW continuous wave (CW) Nd:YAG laser. The influences of laser welding velocity, flow rate of side-blow shielding gas, defocusing distance were investigated. Microstructure of the welded seam was characterized by optical microscopy (OM), scanning electron microscopy (SEM) and X-ray diffraction (XRD) and energy dispersive spectrometer (EDS). Mechanical properties of the welded seam were evaluated by microhardness and tensile strength testing. Results show that high quality full penetration laser-welded joint can be obtained by optimizing the welding velocity, flow rate of shielding gas and defocusing distance. The laser-welded seam have non-equilibrium solidified microstructures consisting of γ-FeCr0.29Ni0.16C0.06 austenite solid solution dendrites as the dominant and very small amount of super-fine dispersed Ni3Al γ' phase and Laves particles as well as MC needle-like carbides distributed in the interdendritic regions. Although the microhardness of the laser-welded seam was lower than that of the base metal, the strength of the joint was equal to that of the base metal and the fracture mechanism showed fine ductility
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S0169-4332(07)00444-8; Copyright (c) 2007 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
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ALUMINIUM OXIDES, CARBIDES, CARBON COMPOUNDS, CHROMIUM ALLOYS, CHROMIUM COMPOUNDS, FERRITE GARNETS, HEAT RESISTING ALLOYS, IRON COMPOUNDS, LASER RADIATION, LASER WELDING, METALS, MICROHARDNESS, MICROSTRUCTURE, MOLYBDENUM ALLOYS, NICKEL COMPOUNDS, OPTICAL MICROSCOPY, SCANNING ELECTRON MICROSCOPY, SOLID SOLUTIONS, SPECTROMETERS, STEELS, THICKNESS, X-RAY DIFFRACTION
ALLOYS, ALUMINIUM COMPOUNDS, CARBON ADDITIONS, CARBON COMPOUNDS, CHALCOGENIDES, COHERENT SCATTERING, DIFFRACTION, DIMENSIONS, DISPERSIONS, ELECTROMAGNETIC RADIATION, ELECTRON MICROSCOPY, ELEMENTS, FABRICATION, HARDNESS, HEAT RESISTANT MATERIALS, HOMOGENEOUS MIXTURES, IRON ALLOYS, IRON BASE ALLOYS, JOINING, MATERIALS, MEASURING INSTRUMENTS, MECHANICAL PROPERTIES, MICROSCOPY, MINERALS, MIXTURES, OXIDE MINERALS, OXIDES, OXYGEN COMPOUNDS, RADIATIONS, SCATTERING, SOLUTIONS, TRANSITION ELEMENT ALLOYS, TRANSITION ELEMENT COMPOUNDS, WELDING
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Pawar, S.M.; Moholkar, A.V.; Rajpure, K.Y.; Bhosale, C.H., E-mail: spawar_81@yahoo.co.in, E-mail: chb_phy@unishivaji.ac.in2007
AbstractAbstract
[en] The CdSe and Fe doped CdSe (Fe:CdSe) thin films have been electrodeposited potentiostatically onto the stainless steel and fluorine doped tin oxide (FTO) glass substrates, from ethylene glycol bath containing (CH3COO)2.Cd.2H2O, SeO2, and FeCl3 at room temperature. The doping concentration of Fe is optimized by using (photo) electrochemical (PEC) characterization technique. The deposition mechanism and Fe incorporation are studied by cyclic voltammetry. The structural, surface morphological and optical properties of the deposited CdSe and Fe:CdSe thin films have been studied by X-ray diffraction, scanning electron microscopy (SEM) and optical absorption techniques respectively. The PEC study shows that Fe:CdSe thin films are more photosensitive than that of undoped CdSe thin films. The X-ray diffraction analysis shows that the films are polycrystalline with hexagonal crystal structure. SEM studies reveal that the films with uniformly distributed grains over the entire surface of the substrate. The complete surface morphology has been changed after doping. Optical absorption study shows the presence of direct transition and a considerable decrease in bandgap, E g from 1.95 to 1.65 eV
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S0169-4332(07)00448-5; Copyright (c) 2007 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
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ABSORPTION, CADMIUM SELENIDES, CRYSTAL STRUCTURE, DOPED MATERIALS, ELECTROCHEMISTRY, ELECTRODEPOSITION, FLUORINE, FLUORINE ADDITIONS, GLASS, GLYCOLS, IRON ADDITIONS, IRON CHLORIDES, OPTICAL PROPERTIES, POLYCRYSTALS, SCANNING ELECTRON MICROSCOPY, SELENIUM OXIDES, STAINLESS STEELS, SUBSTRATES, SURFACE PROPERTIES, TEMPERATURE RANGE 0273-0400 K, THIN FILMS, TIN OXIDES, VOLTAMETRY, X-RAY DIFFRACTION
ALCOHOLS, ALLOYS, CADMIUM COMPOUNDS, CARBON ADDITIONS, CHALCOGENIDES, CHEMISTRY, CHLORIDES, CHLORINE COMPOUNDS, COHERENT SCATTERING, CRYSTALS, DEPOSITION, DIFFRACTION, ELECTROLYSIS, ELECTRON MICROSCOPY, ELEMENTS, FILMS, HALIDES, HALOGEN COMPOUNDS, HALOGENS, HIGH ALLOY STEELS, HYDROXY COMPOUNDS, IRON ALLOYS, IRON BASE ALLOYS, IRON COMPOUNDS, LYSIS, MATERIALS, MICROSCOPY, NONMETALS, ORGANIC COMPOUNDS, OXIDES, OXYGEN COMPOUNDS, PHYSICAL PROPERTIES, SCATTERING, SELENIDES, SELENIUM COMPOUNDS, SORPTION, STEELS, SURFACE COATING, TEMPERATURE RANGE, TIN COMPOUNDS, TRANSITION ELEMENT ALLOYS, TRANSITION ELEMENT COMPOUNDS
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AbstractAbstract
[en] Silicon carbonitride (Si:C:N) films produced by the remote microwave hydrogen plasma chemical vapor deposition (RP-CVD) using bis(dimethylamino)methylsilane as single-source precursor and hydrogen as an upstream gas for plasma generation, were examined in terms of their physical (density) and mechanical (hardness, elastic modulus, friction coefficient, and 'plasticity index') properties. The effect of substrate temperature (varied in the range of 30-400 oC) on the properties of Si:C:N films is presented. A reasonable compositional and structural dependencies of film properties were determined using, respectively, the XPS atomic concentration ratios N/Si and C/Si, as well as the relative integrated intensities of the IR absorption bands from the Si-N and Si-C bonds (controlled by deposition temperature), evaluated in the first part of this work. In view of their good mechanical properties, Si:C:N films seem to be useful coatings for improving surface mechanics of engineering materials
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S0169-4332(07)00463-1; Copyright (c) 2007 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
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ABSORPTION, CARBONITRIDES, CHEMICAL VAPOR DEPOSITION, COATINGS, CONCENTRATION RATIO, DENSITY, FILMS, FRICTION FACTOR, HARDNESS, HYDROGEN, MECHANICAL PROPERTIES, MICROWAVE RADIATION, ORGANIC SILICON COMPOUNDS, PHYSICAL PROPERTIES, PLASMA, PLASTICITY, SILICON COMPOUNDS, SUBSTRATES, SURFACES, TEMPERATURE RANGE 0273-0400 K, TEMPERATURE RANGE 0400-1000 K, X-RAY PHOTOELECTRON SPECTROSCOPY
CARBON COMPOUNDS, CHEMICAL COATING, DEPOSITION, DIMENSIONLESS NUMBERS, ELECTROMAGNETIC RADIATION, ELECTRON SPECTROSCOPY, ELEMENTS, MECHANICAL PROPERTIES, NITROGEN COMPOUNDS, NONMETALS, ORGANIC COMPOUNDS, PHOTOELECTRON SPECTROSCOPY, PHYSICAL PROPERTIES, RADIATIONS, SORPTION, SPECTROSCOPY, SURFACE COATING, TEMPERATURE RANGE
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Oliveira, V.; Colaco, R.; Vilar, R., E-mail: vitor.oliveira@ist.utl.pt2007
AbstractAbstract
[en] Previous work by the authors on micromachining of Al2O3-TiC ceramics using excimer laser radiation revealed that a columnar surface topography forms under certain experimental conditions. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) observations show that the columns develop from small globules of TiC, which appear at the surface of the material during the first laser pulses. To understand the mechanism of formation of these globules, a 2D finite element ablation model was developed and used to simulate the time evolution of the temperature field and of the surface topography when a sample of Al2O3-TiC composite is treated with KrF laser radiation. Application of the model showed that the surface temperature of TiC rises much faster than that of Al2O3, but since TiC has a very high boiling temperature, its vaporization is significant only for a short time. By contrast, the surface temperature of Al2O3 rises above its boiling temperature for a much longer period, leading to a greater ablation depth than TiC. As a result, a small TiC globule stands above the Al2O3 surface. The results of the model are compared with experimental measurements performed by AFM. After three pulses, the height of the globules predicted by the model is about 340 nm, in good agreement with the height measured experimentally, about 400 nm
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S0169-4332(07)00513-2; Copyright (c) 2007 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
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ALUMINIUM COMPOUNDS, CALCULATION METHODS, CARBIDES, CARBON COMPOUNDS, CHALCOGENIDES, DIMENSIONS, ELECTRON MICROSCOPY, EXCIMER LASERS, GAS LASERS, LASERS, MATHEMATICAL SOLUTIONS, MICROSCOPY, NUMERICAL SOLUTION, OXIDES, OXYGEN COMPOUNDS, PHASE TRANSFORMATIONS, TITANIUM COMPOUNDS, TRANSITION ELEMENT COMPOUNDS
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