Résumé: In this research, combustion synthesis in a self-catalytic propagation high temperature synthesis mode (SCHS) and arc discharge technique was used with the aim to synthesize 1D carbon nanostructures, by the sodium Azide NaN3 reduction of the Teflon PTFE (CF)n, in argon, at ambient pressure of 1 MPa. In the same time, several possible catalysts were tried like such as Fe(CO)5, Co(CO)5, Ni(CO)5 powders. Through the presence of NaF in the product, the deep reduction of PTFE is shown in order to produce fullerenes and carbon nanotubes. On one hand, we obtained nanocarbon reinforced iron nano-composites by nanocarbon encapsulated iron metal nanoparticles in nanocarbon coke in our samples with high yield. This opens the process to new possible and nanobiotechnology applications as markers and therapy of cancer and in drug delivered by using nanocarbon containers encapsulated (ferromagnet is the heater of cancer tissue, markers and drugs). On the other hand, the functionalized nanocarbon by magnetic hydroxipatite and cellular growth near nanocarbon for neural prosthetics is now in progress.

Résumé: Effect of yttrium on glass-forming ability (GFA), thermal stability and mechanical properties of glassy Fe-Cr-Mo-C-B-Yalloy were studied. Amorphous alloys with composition (at %) Fe 48 Cr 15 Mo 14 C 15 B 6 Y 2 were prepared by usinga commercial AISI430 steel as a base material. In the case of a bulk metallic glass (BMG), are prepared by usingcommercial grade raw materials, rods of 2 mm diameter are obtained by copper mold casting. Ribbons of width 5 mm and thickness about 30 µm are prepared from the arc- melted ingots using a single roller melt spinner at a wheel speed of 40 m/s. The thermal and structural properties of the samples are measured by a combination of differential scanning calorimetric (DSC), x-ray diffraction and scanning electron microscopy. Chemical compositions are checked by energy dispersive spectroscopy analysis. X-ray diffraction and scanning electron microscopy observations confirm that an amorphous structure is obtained in all the samples. A minor fraction of crystalline phases (oxides) is detected on the as cast surface. Values of hardness and Young modulus were measured by Nanoindentation for both the alloys. The effects of adverse casting conditions (such as air atmosphere, non-conventional injection copper mold casting and partial replacement of pure elements with commercial grade raw materials) on the glass formation and properties of the alloy are discussed

Résumé: A polycrystalline dense Ti3SiC2 based ceramic material has been produced by several techniques. The effect of addition of TiC and SiC is also studied. The Ti3SiC2 material shows extraordinary electrical, thermal and mechanical properties. Furthermore, it shows a damage tolerance capability and oxidation resistance. In this work, we have synthesized Ti3SiC2 by electro-thermal explosion chemical reaction (ETE) with high current density (900 Amperes/a.u) followed by uniaxial pressure. The structural properties of the as-prepared materials are studied by x-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive x-ray spectroscopy (EDX) techniques. The chemical cartography, imaging and electronic properties are investigated using Ultra- STEM and electron high energy loss resolution spectroscopy (EELS) techniques, respectively. The surface of Ti3SiC2 is characterized by means of X-ray photoelectron spectroscopy (XPS). High resolution C 1s, Si 2p, Ti 2p, Ti 3s core level spectra are explained in terms of crystallographic and electronic structure. Valence band spectrum is performed to confirm the validity of the theoretical calculations.

Résumé: A polycrystalline dense Ti3SiC2 based ceramic material has been produced by several techniques. The effect of addition of TiC and SiC is also studied. The Ti3SiC2 material shows extraordinary electrical, thermal and mechanical properties. Furthermore, it shows a damage tolerance capability and oxidation resistance. In this work, we have synthesized Ti3SiC2 by electro-thermal explosion chemical reaction (ETE) with high current density (900 Amperes/a.u) followed by uniaxial pressure. The structural properties of the as-prepared materials are studied by x-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive x-ray spectroscopy (EDX) techniques. The chemical cartography, imaging and electronic properties are investigated using Ultra-STEM and electron high energy loss resolution spectroscopy (EELS) techniques, respectively. The surface of Ti3SiC2 is characterized by means of X-ray photoelectron spectroscopy (XPS). High resolution C 1s, Si 2p, Ti 2p, Ti 3s core level spectra are explained in terms of crystallographic and electronic structure. Valence band spectrum is performed to confirm the validity of the theoretical calculations.

Résumé: In the present work, the glass formation of Zr59Nb5Cu18Ni8Al10 (numbers indicate at %) alloy with diameter of 2 mm was prepared through water-cooled copper mold casting and in a ribbon form by the single roller melt-spinning method. This study is primarily devoted to evaluating the results obtained with the two methods of the development. The thermal stability was evaluated by differential scanning calorimetry (DSC) at a heating rate of 10°C/mn. The characteristic data of the bulk metallic glass are presented, including glass transition temperature (Tg) and crystallization temperature (Tx). The microstructure and constituent phases of the alloy composite have been analyzed by using X-ray diffraction, and observed by Scanning Electron Microscopy (SEM). The mechanical properties of bulk Zr59Nb5Cu18Ni8Al10 were alloy measured by compression tests at room temperature.

Résumé: In the present work, the formation of amorphous phase as primary phase was found in Zr59Cu18Ni8Al10X5 (XP%Nb,Ti andTa) glassy alloys. Wedge shaped bulk samples, with thickness form 2 mmup to 5mm,were prepared bycoppermould casting technique.Ribbons of the same composition,with 30µm thickness, were prepared by melt spinning technique. The thermal stability and structural properties were evaluated by differential scanning calorimetry (DSC) andX-raydiffraction (XRD), respectively.The effect of high temperature on the isothermal crystallization of Zr59Cu18Ni8Al10X5 (XP%Nb,Ti andTa) bulk metallic glass rodwith a diameter of 2mmwas investigated byHTX-ray diffraction. It was found that the crystallization behaviour of Zr59Cu18Ni8Al10X5 (XP%Nb, Ti and Ta) bulkmetallic glass strongly depends onthe annealing temperature.The different crystallization behaviour is believed to be due to the different structures that the metallic glass possesses at different temperatures.

Résumé: study describes a study on the magnetic properties of amorphous Tb1-x Cox binary films prepared by sputtering. Results are given for the composition dependence of Curie temperature and magnetization on the room temperature. The aim of this work is to study the magnetic properties of Tb1.Cox amorphous alloys with respect to the composition. Magnetizations processes have been studied over a wide range of fields (up to 8 Tesla) and temperature range (10-300 K) by using a vibrating sample magnetometer (VSM). The magnetic properties for Tb1-x Cox have been investigated in a range of 0.48sxs0.78. We have found a large anisotropy at room temperature with ordering temperatures up to about 600 K. For the samples which are ferromagnetic at room temperature (i.e., x > 0.62). The hysteresis loops describe the intrinsic anisotropy which can be analysed in terras of a biaxial anisotropy. No saturation was observed for fields up to 8 T due to the sperimagnetic nature of such materials.

Résumé: The aim of the work is to study the magnetic properties of Tb1-x Cox amorphous alloys with respect to the composition and annealing temperature. The samples have been prepared by the dc triode co-sputtering. The most important results are: (1) Curie temperature is higher than the room temperature for the magnetic samples with Co content x>0.6, before annealing rises T with Co content. Crystallization commences at approximately 400°C. (2) A significant high field susceptibility, even up to 8 Tesla, confirms the sperimagnetic structure. (3) A biaxial anisotropy occurs before annealing due to stress, but a uniaxial anisotropy is induced by the field annealing; the anisotropy value is dependent upon composition.

Résumé: Les facteurs acentriques de 18 composés hydroxylés (alcools, phénols), ont été corrélés linéairement avec 2 descripteurs moléculaires de type géométrique sélectionnés par algorithme génétique, parmi plus de 1600 calculés en utilisant le logiciel de modélisation moléculaire DRAGON. Les différentes statistiques établies (coefficient de détermination multiple et de prédiction ; racines des erreurs quadratiques moyennes ; test de randomisation) montrent la qualité, la robustesse et les bonnes capacités prédictives internes du modèle construit. Aucune observation aberrante ou influente n’a été relevée.

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Résumé: Carbon nanotubes are prepared by the technic of self-propagating high-temperature synthesis for the first time. The depart components for this synthesis are carboniferous materials (soda, limestone, and Teflon) and reducers (magnesium, lithium, and sodium) with addition of a nickel and cobalt catalyst. The morphology of the nanotubes (straight multiwall nanotubes apparently free of a catalyst, bent nanotubes completely filled with a catalyst, and carbon Nano fibers) is similar to that of nanotubes grown by chemical methods (CVD, CCVD, MWPCVD). The nanotubes account for 6-13 wt % of the product synthesized. A Simple model for lithium intercalated (10, 10) nanotube is developed. The electronic, optic, structural properties, storage capacity; and estimation of the charge transfer in the loss function of the n-type doping Li-intercalated bundles of single-walled carbon nanotubes (SWCNTs) by the two-zone vapors method have been studied using HRTEM, HREELS and electron diffraction.