Publications: Articles
2014 | |
Articles: | |
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Nuclear Instruments and Methods in Physics Research B: Beam Interactions with Materials and Atoms,
326:341-344
2014
Resume: The deposition of multiple carbon atoms on a crystalline silicon (Si) surface is modelled at 5 eV energy by using molecular dynamics simulations combined with a third generation force field that includes bond breaking and formation. Force field parameters are taken from a previous work. These simulations allow for atomic scale insights into the deposition mechanisms and an easier comparison with experimental observations. The results, including distributions of implantation depth, carbon concentrations, sticking coefficients, radial distribution function, and angular distributions are compared for different incidence angles. Due to the deposition of carbon atoms inside the silicon structure, silicon carbide starts to form. The crystalline structure has been investigated for different conditions to get a better understanding of the damaging and growth mechanisms. It is found that a lot of deformation is accumulated in the area of deposition near to the surface but underneath the surface the silicon has still a more crystalline structure. The variation of the silicon (carbide) structu re slightly depends on the angle of incidence. For the conditions used for these simulations, the sticking probability is always high and varies between 95% and 100%, which can be attributed to the high affinity of carbon for silicon. Equipe: Département CP2S : Expériences et Simulations des Plasmas Réactifs - Interaction plasma-surface et Traitement des Surfaces ESPRITS |
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METALLURGICAL AND MATERIALS TRANSACTIONS B-PROCESS METALLURGY AND MATERIALS PROCESSING SCIENCE,
45(1):13-21
2014
ISSN: 1073-5615
Resume: Gas-stirring ladle treatment of liquid metal has been pointed out for a long time as the processing stage is mainly responsible for the inclusion population of specialty steels. A steel ladle is a complex three-phase reactor, where strongly dispersed inclusions are transported by the turbulent liquid metal/bubbles flow. We have coupled a population balance model with CFD in order to simulate the mechanisms of transport, aggregation, flotation, and surface entrapment of inclusions. The simulation results, when applied to an industrial gas-stirring ladle operation, show the efficiency of this modeling approach and allow us to compare the respective roles of these mechanisms on the inclusion removal rate. The comparison with literature reporting data emphasizes the good prediction of deoxidating rate of the ladle. On parallel, a simplified zero-dimensional model has been set-up incorporating the same kinetics law for the aggregation rate and all the removal mechanisms. A particular attention has been paid on the averaging method of the hydrodynamics parameters introduced in the flotation and kinetics kernels. Equipe: Centre de Compétences : ERMIONE informatique et calcul |
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NATURE,
506(7488):349-354
2014
ISSN: 0028-0836
DOI: 10.1038/nature12952
Equipe: Département P2M : Surfaces et Spectroscopies |
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Materials Characterization,
98:193-201
2014
ISSN: 1044-5803
Equipe: Département SI2M : Microstructures et Contraintes |
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PHYSICAL REVIEW LETTERS,
113(10)
2014
ISSN: 0031-9007
Equipe: Département CP2S : Métallurgie et Surfaces |
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Physical Review B - Condensed Matter and Materials Physics,
90(3)
2014
Equipe: Département P2M : Nanomagnétisme et Electronique de Spin |
2013 | |
Articles: | |
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Journal of Nuclear Materials,
438:S846-S851
2013
Equipe: Département CP2S : Expériences et Simulations des Plasmas Réactifs - Interaction plasma-surface et Traitement des Surfaces ESPRITS |
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ISIJ INTERNATIONAL,
53(2):213-220
2013
ISSN: 0915-1559
Resume: The present study aims to understand the melting of the consumable electrode in the VAR process and gain some insight into the influence of an ensemble arc motion on the melting behaviour. In a previous study, a 2D axisymmetric model of the heat transfer in the cathode had been developed. Using the operating parameters as model inputs, it enabled prediction of the melt rate and the evolution of the melting area. Model results were successfully compared to melt rate measurements in an industrial VAR furnace. In recent years, it has been claimed that the electric arc may not be considered as steady and axisymmetric. Our experimental investigation of the luminosity recorded during an actual VAR heat confirms that a transient 3D behaviour may take place. Therefore, a 3D version of the previous model was set up to predict the heat transfer and melting of the electrode, using the unknown ensemble arc motion as an input. The arc is assimilated to a transient distribution of energy flux density. Results evidence that the influence of the arc motion on the shape of the electrode tip can be very important. In industrial practice, the cathode tip usually remains relatively flat during melting. The shapes of the computed electrode tips enable us to propose some arc parameters which remain compatible with both the periodic behaviour of the light emitted and the flatness of the electrode. Equipe: Centre de Compétences : ERMIONE informatique et calcul |
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Plasma Processes and Polymers,
10:535-543
2013
Resume: Poly-lactic acid (PLA) is the most used biopolymer in both biomedical and food packaging fields to replace petrochemical plastics. The surface properties of PLA thin films were studied before and after plasma treatment to enhance its wettability and its adhesive properties. Based on the experimental design, the most significant parameters of the plasma process were specified. The effect of the cold plasma treatment on the mechanical, topographic composition, thermal and barrier properties of the PLA was carried out using different Ar-N2-O2 gas mixture. Results show that the discharge gas can have a significant influence on the chemical composition and the wettability of the PLA surfaces. As the plasma processing is a surface treatment without affecting the bulk properties, it did not change the PLA properties. Equipe: Département CP2S : Expériences et Simulations des Plasmas Réactifs - Interaction plasma-surface et Traitement des Surfaces ESPRITS |
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Sensors and Actuators, B: Chemical,
185:309-320
2013
Equipe: Centre de Compétences : MiNaLor micro et nanotechnologies |