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Pernot, Paul. "Élaboration et caractérisation de composés binaires et ternaires du graphite avec les chlorures métalliques : Corrélations entre structures et propriétés physiques". Nancy 1, 1989. http://www.theses.fr/1989NAN10236.
Pełny tekst źródłaTousch, Corentin. "Incorporation de nanotubes de carbone dans les couches d’oxyde formées par le procédé d’oxydation par plasma électrolytique de l’aluminium en vue d’élaborer des couches d’oxyde conductrices". Electronic Thesis or Diss., Université de Lorraine, 2023. http://www.theses.fr/2023LORR0282.
Pełny tekst źródłaThe most common method to enhance the surface properties of aluminum is acid-based anodization, forming a protective layer of aluminum oxide on the metal surfaces. This imparts improved wear and corrosion resistances due to alumina's high hardness and chemical stability. However, aluminum oxide is a strong electrical insulator, substantially increasing contact resistance in anodized components. Traditional electrolytic surface treatments involving nickel, cadmium, and chromium maintain electrical conductivity but involve heavy metal-containing electrolytes, including carcinogenic hexavalent chromium, a substance facing European Union import restrictions. Consequently, alternative treatments are sought, leading to electrolytic plasma oxidation. This electrochemical conversion process differs from acid anodization, using higher current/voltage and dilute basic electrolytes. The resulting oxide layer is porous, enabling the incorporation of solid particles. These particles are dispersed in the electrolyte and gradually incorporated within the growing oxide layer. By adding conductive particles it is conceivable to create percolation paths, forming a composite aluminum oxide-particle layer that protects the underlying aluminum while maintaining low electrical contact resistance.Carbon nanotubes were chosen for their excellent electrical conductivity and high form factor, enabling percolation at low volume concentration. The study aims at incorporating carbon nanotubes into the oxide layer generated during aluminum plasma electrolytic oxidation to produce conductive oxide layers. Experimental investigations establish fundamental insights into incorporation mechanisms, impact of electrical parameters, the influence of carbon nanotubes on the process, and coating properties, especially electrical behavior. Results reveal that carbon nanotubes accelerate layer growth and increase oxide coating porosity. High concentrations yield excessively porous layers with defects (cracks, delamination), compromising layer integrity. Carbon nanotubes in both the electrolyte and the growing oxide substantially affect the process. Transition to "soft" micro-discharge regime shifts earlier with higher nanotube concentrations under suitable electrical conditions. Excessive nanotube concentrations inhibit the process, preventing oxide layer formation. "Arc" regime treatments favor nanotube incorporation in the oxide compared to "soft" regime treatments. Although carbon nanotube incorporation significantly enhances oxide layer electrical conductivity, the percolation threshold isn't reached, and layers remain insulating for now. Despite this, the results are highly promising, prompting further research to optimize electrical conductivity in these composite coatings, building upon the findings reported here
Sakata, Hironobu. "Propriétés électriques et mécaniques de couches minces d'oxydes déposés sous vide". Bordeaux 1, 1986. http://www.theses.fr/1986BOR10530.
Pełny tekst źródłaBlanc-Mignon, Marie-Françoise. "Influence de la technologie de fabrication sur les propriétés électriques des structures capacitives MIS". Lyon, INSA, 1990. http://www.theses.fr/1990ISAL0068.
Pełny tekst źródła[The shrinkage of the VLSI circuits size, requires research in new gate and dielectric materials. The refractory metals and their silicides advantageous because of a higher conductivity than aluminium and polysilicon. The electrical characterization of tungsten and tungsten silicides gate MOS structures,allows to exhibit the influence of the technological deposition parameters : sputtering and post deposition annealing induce a diffusion of impurities in the oxide and at the interface deforming the capacitance voltage characteristics. The oxide nitridation yields a dielectric better adapted for the VLSI requirements than the simple oxidation of silicon(higher breakdown field impurities barrier). Electrical analysis (capacitance measurement Tunnelling and avalanche injection) ,of the plasma nitrated oxide MIS structure,gives the evolution as a function of the nitration time,of the trapping in the insulating volume and at the silicon insulating interface,as well as the traps characteristics. Plasma nitration improves the dielectric quality when the nitration time does not exceed one hour. Trapping in the volume is decrease and the interface degradation limited. ]
Porre, Olivier. "Etude de traitements à l'aluminium sur les propriétés électriques de plaquettes et de cellules solaires au silicium multicristallin". Aix-Marseille 3, 1994. http://www.theses.fr/1994AIX30064.
Pełny tekst źródłaBertheville, Bernard. "Propriétés électriques à fréquence variable de produits de décomposition d'une micelle de sulfonate de calcium. Etude corrélative d'oxydes de Ca et de Mg". Montpellier 2, 1993. http://www.theses.fr/1993MON20224.
Pełny tekst źródłaDebreuille-Gresse, Marie-Françoise. "Synthèse, structure et propriétés de composés du bismuth et d'anions phosphate ou vanadate". Lille 1, 1986. http://www.theses.fr/1986LIL10049.
Pełny tekst źródłaRenaut, Nicolas. "Amélioration des propriétés thermomécaniques et ignifuges du polypropylène : applications aux matériels électriques". Thesis, Lille 1, 2008. http://www.theses.fr/2008LIL10137/document.
Pełny tekst źródłaOur study deals with the processes used in order to improve the thermomechanical and fire retardant (FR) properties of polypropylene (PP) materials used in electrical equipments. The fIfst chapter concerns the improvement of the thermomechanical properties trough the development of polymer alloys. Bisphenol A polycarbonate (PC) is used as modifying polymer in the PP matrix. To improve the compatibilization of the polymer blends, two compatibilizing agents (AC) have been evaluated but the obtained properties are not sufficient and thus improvement of the properties was thus achieved using inorganic fillers. The second chapter is about the processes for imparting flame retardancy to PP materials reinforced by mineraI fillers (mica, talc or calcium carbonate). Two types of FR additives are tested: a phosphorous compound (APP: ammonium polyphosphate) used in intumescent systems and various brominated compounds. ln the case of the composite materials containing calcium carbonate, interactions between APP and fillers are evidenced and restrict the development of the protective thermally insulating structure (char) resulting in low FR properties whereas formulations with brominated compound present acceptable properties. However Br compounds present sorne environmental concerns. As a consequence, the last chapter deals with the processes that allow imparting flame retardancy to the PP composites surface. Before applying a FR protective paint, the materials are treated by low pressure radiofrequency cold plasma (O2, Ar, pure or mixture of them). By means of a global analysis of the topography, the surface chemical composition evolution and wettability, we propose sorne rearrangement mechanisms occurring at the PP matrix surface. We demonstrate that these mechanisms influence the adhesive properties of the treated materials and differ for each material as a function of the composition and nature of the fillers
Sassi, Zina. "Etude des spectres vibrationnels et des propriétés électriques des hexahydridoaluminates alcalins Li3AlHnD6-n n=(0,1,2,4,5,6) et de Na3AlH6". Lyon, INSA, 1988. http://www.theses.fr/1987ISAL0024.
Pełny tekst źródłaBouncer, Azzedine. "Caractérisation des contacts Schottky élaborés sur des couches de GaSb obtenues par épitaxie par jet moléculaire". Montpellier 2, 1993. http://www.theses.fr/1993MON20115.
Pełny tekst źródłaNicoud, Sarah. "Composés inorganiques innovants par manipulation et diversification du sous-réseau anionique". Thesis, Lille 1, 2018. http://www.theses.fr/2018LIL1R053/document.
Pełny tekst źródłaThis manuscript details the discovery of new oxide and oxysulfides materials. First, it focuses on the study of hexagonal compounds RM2O4 and R2M3O7 topotactically modified by oxidation. The two metastable compounds, YbFe2O4.5 and InFe2O4.5, show the conservation of the multilayer feature via a sliding of the iron’s and rare earth’ layer and a reorganization of the anionic sublattice. The modulated structures have a unique distribution of FeOn polyhedra (n = 4, 5 and 6). In contrast, the InGaFeO4.3 compound shows the particularity of Ga3+ cations to block the structural rearrangement. The R2M3O7 (Yb2Fe3O7.5 and In2Ga2MnO7.12) compounds have the RM2O4 units already discussed and, therefore, exhibit the same phenomenon of oxidation. Secondly, the study focuses on the research of new oxysulfides of lower dimension, by focusing on the compounds Ba3VS3(VO3S) and La3SiS4(CuS3). Two new structures Ba10V6S7O18 et Ba10.67V3O6Fe8.67S17.33 have been obtained with a low dimension framework made possible by the presence of Ba2+ cations and V(O,S)4 entities which are separators. The first phase opens the way to band gap engineering from the different types of anions including “isolated” sulfurs. The two other new phases Ba3(V,Cr)S3(VO3S) and La3Cu0.5 2δFe0.25+δSiS7 are made up of chains ((Cr/V)3+S3 and deficient (Fe2+/Cu+)S3) separated by tetrahedral entities (VO3S and SiS4).This study is conclude with the structural determination of Co7S8, a binary compound of Co-S system, and the discovery of it unconventional metallic behavior
Boulouz, Abdellah. "Caractérisation de matériaux thermoélectriques à base de semi-conducteurs V2-VI3 déposés par MOCVD : Réalisation de micromodules Peltier et de capteurs thermoélectriques". Montpellier 2, 1999. http://www.theses.fr/1999MON20103.
Pełny tekst źródłaFollet-Houttemane, Claudine. "Les phases oxyfluorées du système Bi2O3-PbO-PbF2 : stabilité - propriétés électriques - caractéristiques structurales". Lille 1, 1987. http://www.theses.fr/1987LIL10215.
Pełny tekst źródłaJacq, Philippe. "Complexes chiraux mésogènes dérivés du butadiène-fer-tricarbonyle". Lyon 1, 1994. http://www.theses.fr/1994LYO10202.
Pełny tekst źródłaBouad, Nathalie. "Mise au point d'un procédé d'élaboration de matériaux thermoélectriques pour thermogénérateur. Potentialités de la mécanosynthèse d'alliages à base de tellurure de plomb". Montpellier 2, 2001. http://www.theses.fr/2001MON20036.
Pełny tekst źródłaCastelan, Philippe. "Contribution à l'étude des propriétés électriques et du phénomène de vieillissement des thermistances C. T. N. à base de manganites à valence mixte". Toulouse 3, 1993. http://www.theses.fr/1993TOU30005.
Pełny tekst źródłaZurletto, Claude. "Influence de recuit à 425o C sur des propriétés électriques du silicium polycristallin : action d'une interface aluminium-silicium". Aix-Marseille 3, 1988. http://www.theses.fr/1988AIX30053.
Pełny tekst źródłaBenyahia-Bentadjine, Sonia. "Mécanismes de formation et propriétés physico-chimiques et mécaniques des interphases epoxy-diamine/métal". Lyon, INSA, 2000. http://www.theses.fr/2000ISAL0025.
Pełny tekst źródłaThe interfacial reactivity between epoxy (DGEBA) and diamine (IPD) monomers and metallic substrates (titanium, aluminum and gold) has been studied using various analytical techniques. Chemical, physical and mechanical properties of organic coatings were determined as a function of their thickness and compared to bulk values. An interphase having specific properties and quite different to polymer bulks ones was underlined. Interphase properties were found to be affected by the substrate nature, metallic surface treatments, the diamine nature (whether aromatic, aliphatic or cycloaliphatic) and the stoechiometric ratio of epoxy-amine mixture. Reaction mechanisms leading to the interphase formation were determined by studying "modified" monomers by hydrated oxide layer. It was found that the diamine monomer reacts with the metallic surface and induces a chemical etching. Then metallic ions then diffuse through the organic layer to form metal-amine complexes. When a saturation threshold was reached, crystals of modified monomers were observed at room temperature. These complexes induce phase separation during the cure cycle of the epoxydiamine mixture leading to a new network formation. The understanding of these phenomena, allows us to produce bulk materials having the same properties than thin films or interphase
Kellouch, Abdelhafid. "Stabilité, effet d'adition et propriétés d'intermétalliques et d'alliages à précipitation : étude numérique (ab initio) des bases Cu et Fe-Al". Besançon, 2004. http://www.theses.fr/2004BESA2002.
Pełny tekst źródłaThis work consists in applying a computational method based on the quantum mechanical calculations ( ab inition method) to metal alloys. This method is used to determine the general tendencies which characterize their behaviours as well as to improve their physical properties (mechanical, transport etc). The calculations were carried out to study the effects of the ternary additions 3d (Ti, V, Cr) and 4d (Zr, Nb, Mo) on the mechanical and transport properties of the Cu-Ag alloys as well as the effects of small atoms (B, C, N, O) and the deviation from the stoechiometry in the FeAl alloys. The stability of the second phases that can reinforce the pure matrix were also investigated: Laves structures for the Cr-Zr-Nb system and their behaviour at high temperatures in Cu-based alloys, Heusler structure Fe2AlTi and Fe2AlCr for FeAl. The calculations were also extended to the ultra-fine Cu/Ag and Cu/AgZr films (multilayer) since they present a possible development by the growth techniques recently acquired by the laboratory (in particular PVD and CVD techniques). Finally, this study also showed the potential of the ab inition method for the design of new materials by combining the effects of temperature, concentration, defects. Etc. Knowing the tendencies and the correlation between the microscopic and macroscopic properties, the designer can be well guided for the development of new alloys with the required properties without making expensive experiments
Leclercq, Bastien. "Unités ferromagnétiques « basse D » : frustration et transitions méta-magnétiques pour la mise en place de couplages magnétoélectriques". Thesis, Lille 1, 2019. http://www.theses.fr/2019LIL1R078.
Pełny tekst źródłaDespite their immense interest, scope and applications of magnetoelectrics materials are still a rarity, their use has been hindered by the weakness of the polarization generated by magnetoelectric effect (e.g. BiFeO3) or the low working temperature (e.g. TbMnO3). In these compounds there is a coupling between the ferroelectric and magnetic properties that coexist simultaneously. By the existence of these couplings, these materials are of great interest in particular for electronics applications (sensors, switch, etc) and data storage, allowing to take advantages of both the electrical and magnetic properties. The capacity can thus be doubled, the information can be written electrically taking advantage of the low energy consumption, and read magnetically in a non-destructive way. However, the actual development strategy too often relies on optimization of the few well-known exploitable compounds in the literature, which does not lead to great improvement of the properties. Here we propose an original and thoughtful approach for designing magnetoelectric properties in inorganic compounds, dealing with low dimensional ferromagnetic units (0D blocks, 1D chains, 2D layers) and their alignment under field through metamagnetic transitions. Our candidates possess collinear or canted macrospins of high spin magnetic cations (M = Fe2+, Co2+, Mn2+), separated by non-magnetic and electrical insulating spacers XO4 or X2O7 (X=P, As) or large cations (A=Ba2+, Sr2+) building up the insulating properties. We give particular interest to AM2X2O8 polymorphs and their frustrated network including the first Ising 2D FM oxide BaFe2P2O8, some rare example of low-D ferromagnetic compound with incommensurate structures such as BaMX2O7, but also the M-type Hexaferrites AM12O19. We paid particular attention to the creation of intrinsic magnetic frustrations (triangular lattice and/or cationic substitution), and magnetization steps where the creation of frustrations and magnetic domains during the reorientation of spins under field is expected to be at the origin of enhanced magnetoelectric properties
Cledat-Schneider, Sandrine. "Elaboration et propriétés de composites particulaires AlN-TiB2". Limoges, 1997. http://www.theses.fr/1997LIMO0028.
Pełny tekst źródłaHamdi, Mohamed. "Caractérisations cristallographiques et études des propriétés électriques des composés Cu2Zn(Sn,Si)S4 pour des applications photovoltaïques". Nantes, 2015. http://archive.bu.univ-nantes.fr/pollux/show.action?id=bc57013f-15ae-4a0f-84bf-c093d63691c6.
Pełny tekst źródłaThe installation of solar panels is experiencing strong growth, according to forecasts should still increase short-medium and long term. The different PV technologies are often divided by generations, reflecting the progress of their research and their arrival on the market. As such, the development of a new generation of solar cells based on Cu2Zn(Sn,Si)S4 looks promising. We sum interested in this work to expand the family of these quaternary chalcogenides, by the gradual substitution of tin by silicon, these compounds are named CZTSiS. The RX analysis showing a structural transformation in the series Cu2Zn(Sn,Si)S4, the replacement of tin with silicon leads to a reduction in the volume mesh. Furthermore, the two compounds of this group limits do not have the same crystal structure; it changed a quadratic mesh Cu2ZnSnS4 to orthorhombic mesh Cu2ZnSiS4. These results were confirmed by optical and spectroscopic, studies allowed us to better understand the processes occurring with the insertion of silicon in the matrix studied. To investigate the potential of these new compounds (CZTSiS) as absorbers in solar cells, conductivity measurements were performed using impedance spectroscopy. These results show the existence of different modes of conduction
Laurent, Christophe. "Contribution à l'étude de nanocomposites à matrice céramique. Alumine-alliages fer-chrome et alumine-zircone-fer et alliages fer-chrome". Toulouse 3, 1994. http://www.theses.fr/1994TOU30017.
Pełny tekst źródłaKoukharenko, Elena. "Elaboration et caractérisations microstructurale et électrique de tellurures de bismuth et d'antimoine élaborés par ultratrempe". Montpellier 2, 2000. http://www.theses.fr/2000MON20092.
Pełny tekst źródłaJules, Jean-Charles. "Défauts ponctuels par substitution et conséquences sur les transitions de phase et les propriétés diélectriques dans des composés du type A2BX4 et du type ABO3". Dijon, 1989. http://www.theses.fr/1989DIJOS003.
Pełny tekst źródłaPolo, Valério. "Contribution à l'étude des composes d'insertion du graphite obtenus par action d'hétérocomplexes associant deux chlorures métalliques : cas des chloroaluminates de métaux de transition". Nancy 1, 1994. http://www.theses.fr/1994NAN10062.
Pełny tekst źródłaVautrein, Corinne. "Propriétés électriques et réactivité vis-à-vis de l'oxygène des molybdates mixtes de cobalt-fer Co(1-x)Fe(x)MoO(4) pulvérulents synthétisés par réaction solide-solide". Dijon, 1995. http://www.theses.fr/1995DIJOS010.
Pełny tekst źródłaCorreia, Sandra. "Etude des propriétés électriques, tribologiques et physico-chimiques de revêtements étamés pour des applications en connectique automobile". Paris 11, 2009. http://www.theses.fr/2009PA112021.
Pełny tekst źródłaThe use of tin as a coating for electrical contact is widespread in electronic systems, especially in the automotive industry. Some field conditions can lead to the degradation of the electrical properties of these contacts and bring failure of systems. This problem of reliability becomes more and more critical. The mechanisms involved in the degradations are numerous, complex and involve a large number of parameters. This thesis aims at increasing the knowledge on the impact of the evolution of tin coating on the appearance of electrical failures of connector type contacts. The collaboration between PEM and LGEP allowed to set up both a rigorous process for the fabrication and control of coating and to set a test procedure applied to representative contacts of connector type. Friction and fretting tests are used to assess the coating behaviour. After structurally, chemically, mechanically and electrically characterizing the tin coating usually used in connector applications, the effects of thermal ageing are described. The influence of the formation of intermetallic phases is shown. Various parameters such as the tin coating thickness, the use of an underlayer and its nature are studied. Then it was attempted to minimize the formation of the intermetallic compounds by acting on their growth kinetics. This was achieved by modifying the diffusion processes of the species in the tin layer, in particular by the use of various underlayers. A process of a tin stripping performed on the thermally aged samples allowed to investigate the mechanical properties of the various intermetallic phases formed. The influence of the chemical composition and of the structure of these compounds is shown. Finally it is shown that the use of a thin (0. 1 μm) cobalt underlayer brings a significant improvement of the coating behaviour: fretting degradation of the contacts is postponed even after a heat treatment
Maalal, Rachid. "Propriétés diélectriques et structurales de la phase d'Aurivillius mixte Bi(7)Ti(4)NbO(21)". Limoges, 1994. http://www.theses.fr/1994LIMO0030.
Pełny tekst źródłaNey, Pascal. "Etude de l'origine des propriétés électrooptiques et optiques non linéaires du métaborate de baryum (β-BaB2O4) par spectroscopie Raman". Metz, 1998. http://docnum.univ-lorraine.fr/public/UPV-M/Theses/1998/Ney.Pascal.SMZ9864.pdf.
Pełny tekst źródłaThe work presented in this thesis is devoted to the study of the origin of the electro-optic (EO) and the nonlinear optical (NLO) properties in barium metaborate (β-BBO). A new method for measuring EO coefficients, using a Michelson interferometer, has been developed during the thesis work This method allows to determine the EO coefficients of β-BBO which are used to calculate the ionic contributions. The comparison between the ionic and electronic EO coefficients underlines various behaviours. The microscopic origin of these contributions is analysed by using Raman scattering results as the frequencies and the intensities of the latter vibrations. So, after we have performed an assignment of the Raman vibrations modes of β-BBO, it is possible to link each EO coefficient to a Raman mode. A model is then established which is able to connect the EO coefficient with the properties of the vibrational modes. The various ionic and electronic contributions are estimated from the ratio calculated from the Raman scattering data. The good agreement between the results obtained by EO measurements and those deduced from the vibrational modes demonstrates the validity of the model and at the same time of the method used to estimate the EO coefficients contributions from Raman data. A deeper study allows then to distinguish the motions leading to the appearance of the Raman lines and to detect the mechanism responsible of the EO and NLO effects. So, only the (B3O6)3- rings are concerned by the EO and NLO mechanisms in β-BBO. The anions translations in the plane perpendicular to the optic axis and the rings breathings are the main motions related to the r51 and r22 coefficients. The electronic clouds distortion generated by the distortion of the rings permits to explain the electronic values of r51 and r22
Raynaud, Michèle. "Application des méthodes de la chimie quantique à l'étude de la réactivité et des propriétés électroniques de composés organiques cyanés". Paris 11, 1989. http://www.theses.fr/1989PA112298.
Pełny tekst źródłaBakiz, Bahcine. "Etude de systèmes de matériaux évolutifs : interactions solides-gaz, propriétés catalytiques et électriques dans le cas d'hydroxycarbonates, carbonate et oxydes à base de terres rares (La, Ce, Lu)". Toulon, 2010. https://theses.hal.science/tel-00602907/fr/.
Pełny tekst źródłaThe present work deals with the solid gas interactions between lanthanum and cerium based phases (hydroxycarbonates LaOHCO3, CeOHCO3, carbonate La2O2CO3, and oxides La2O3, CeO2), and the gases CH4, CO and CO2. These interactions might be involved in gas sensor or catalytic applications. The main interest of these rare earth based systems resides in the fact that they are evolving materials in environmental conditions. The initial hydroxycarbonate phases are synthesized via specific precipitation sol-gel routes. The phases La2O2CO3, La2O3 and CeO2 are obtained by thermal treatment of the hydroxycarbonates. The various phases are first characterized by X-ray diffraction. Their crystal sizes and morphologies are then determined by scanning and transmission electron microscopy (SEM, TEM). The catalytic interactions of these polycrystalline solids with air-CH4 and air-CO mixtures are studied making use of Fourier Transform Infrared spectroscopy of emitted gases, at various temperatures (100 to 550°C), and as a function of time. The conversions of CH4 and CO into CO2 are observed from air – gas flows crossing through polycrystalline walls of the polycrystalline catalytic materials. The catalytic efficiency is defined as being proportional to the FTIR absorbed intensities due to the CO2 molecules. These intensities depend on time and temperature. The electrical analyses of compacted pellets are performed by electrical impedance spectrometry at various temperatures. For a given temperature, the conversions of CO and CH4 into CO2 reach a stabilized level after an initiation time. This stabilized level increases with temperature and reaches a maximum value depending on material nature and specific area. The conversion of CO is obtained at temperatures lower than the ones observed for CH4. These time dependent catalytic conversions are modeled from an elemental Avrami’s approach. The carbonatation kinetics are determined first by thermal and thermogravimetry analyses, at fixed temperatures, as a function of time. Two steps in carbonatation are evidenced. Using electrical impedance spectrometry as a function of time and temperature the electrical evolutions of lanthanum and cerium based systems subjected to carbonatation and decarbonatation are analyzed. As a first step, the electrical responses associated with the phase modifications of the hydroxycarbonate phases LaOHCO3 and CeOHCO3 during thermal decomposition under air are determined. Then, the electrical signals due to carbonatation and decarbonatation processes are analyzed: the ionic mobility of CO3 2- ions in the carbonate solid is evaluated. The evolving series LaOHCO3-La2O2CO3 - La2O3 might be of a high interest in gas sensor systems, working at variable temperatures and sensitive to CH4, CO or CO2
Yi, Ji-Hyun. "Préparation par voie sol-gel, caractérisation et propriétés électriques de couches minces ferroélectriques de SrBi2(Nb,Ta)2 O 9". Limoges, 1998. http://www.theses.fr/1998LIMO0017.
Pełny tekst źródłaMartin, Marie-Hélène. "Caractérisation des interfaces acier-fonte-carbone de l'ensemble anodique d'une cuve d'aluminium". Thesis, Université Laval, 2014. http://www.theses.ulaval.ca/2014/30645/30645.pdf.
Pełny tekst źródłaThe aluminum industry faces economical headwinds, thus needing to reduce its operating costs. The project studies specifically energy losses at anode sealing location. Experiments were conducted from room conditions up to the maximum capacity of the bench test. Laboratory work was completed using tri-material samples (made in such a way to replicate accurately reality) and an innovative bench test using magnetic induction as a source of heat that enables minimal heat-up time and sample oxidation during experiments. Non-linear regression was then used to retrieve a model from laboratory results. Analysis showed that a power model represents accurately the interfaces behavior from room to operation conditions. Comparison with literature showed that the order of magnitude is the same but results are not similar. This observation can be explained by the use of slightly different materials and also due to the use of a different experimental procedure.
El-Horr, Nahida. "Synthèses, études structurales et propriétés électriques de polyphosphates contenant du lithium". Grenoble 1, 1988. http://www.theses.fr/1988GRE10078.
Pełny tekst źródłaMartin, Marie-Pascale. "Réalisation de varistances sérigraphiées à base de ZnO pour des applications en électronique de puissance : influence des électrodes sur les propriétés électriques du composant de protection". Bordeaux 1, 2003. http://www.theses.fr/2003BOR16024.
Pełny tekst źródłaThick film screen-printed varistors based on ZnO powder were developped in the aim to protect IGBT power transistors against overvoltages (VS>600V). Hybrid thick film technology has many advantages : proximity of the component, easy choice of geometry or decrease of costs. Feasability of planar thick film screen-printed varistors was demonstrated with a systematic study of fabrication parameters like grain size of powder, firing cycle, mechanical pressure or film thickness. Furthermore, deepened study of the microassembly electrodes/ZnO/Al2O3 showed that : - Degradation of the electrical properties of the microassembly comes from the modification of the composition of grain junctions in ZnO film : bismuth oxide evaporates or migrates in the substrate when varistors are fired. - Restauration of electrical properties of thick film varistors is possible by using relevant electrodes inks which contains necessarily Bi2O3. This restauration depends on electrodes geometry or electrodes inks firing cycle. Depending on electrodes inks compositions and for breakdown voltages 0,5 40 can be compared to those of massive components of same composition. For tests in real conditions, in parallel with an IGBT power transistor (1200V/52A) and submitted to overvoltages, screen-printed varistors clamp the applied voltage and so, protect the component. This varistors (Vs # 500 V) have clamping voltages inferior to 1200V and can dissipate energy density as great as 150 J/cm3
Maire, Bénédicte. "Étude des matériaux à base d'hexaborure de lanthane pour composants résistifs sérigraphiés : Corrélations entre les propriétés électriques et les phénomènes physicochimiques". Bordeaux 1, 1985. http://www.theses.fr/1985BOR10511.
Pełny tekst źródłaThevenot, Sylvain. "Caractérisation & modélisation numérique du comportement chémo-et thermo-résistif en sorption-désorption d'un Composite Polymère Conducteur". Lorient, 2012. http://www.theses.fr/2012LORIS253.
Pełny tekst źródłaThe aim of this work is to improve the understanding of the electrical response of chemo-resistive CPC sensors. EEA-37% CNP was chosen as model system due to its thermoplastic elastomer matrix filled with carbon nanoparticles. In a first step, the use a thin CPC transducers has allowed to demonstrate their good sensing performances for the quantification of barrier effect towards toluene vapour diffusion of montmorillonite platelets filled poly(amide 12) films. A specific experiment was created to study multi-physics phenomena induced in a flat sheet of CPC exposed to a VOC. The simultaneous monitoring of the behaviour of mass, temperature, volume and resistance has produced innovative results to be used to validate the numerical models developed subsequently. Specific experiments established a mathematical relation between solvent concentration and electrical resistivity. The development of a one-dimensional numerical model was found useful to interpret time lags and amplitudes of resistance variations through the visualisation of current densities depending on concentration gradients
Leduc, Bruno, i Bruno Leduc. "Méthode d'évaluation d'assemblages industriels en aluminium liés par adhésifs structuraux". Master's thesis, Université Laval, 2014. http://hdl.handle.net/20.500.11794/25341.
Pełny tekst źródłaCe mémoire entame le développement d’une méthode d’évaluation d’assemblages en aluminium liée par adhésifs structuraux dans un contexte d’ingénierie du secteur industriel. Les travaux ont pour but de fournir à l’entreprise Services Précicad inc. des outils de conception applicables sur le véhicule électrique Kargo. Plus spécifiquement, des séries d’essais expérimentaux sont réalisées sur des échantillons ASTM au moyen de plans d’expériences employant la méthode Taguchi pour étudier l’incidence des conditions de préparation manufacturière sur la résistance mécanique et pour faire un dépistage de produits commerciaux. La famille des méthacrylates est alors privilégiée pour répondre aux besoins de flexibilité d’utilisation et de préparation de surface. Ensuite, différents modèles de calculs analytiques sont étudiés et une analyse paramétrique est réalisée sur le joint en cisaillement à simple recouvrement (SLS). Le modèle du joint sandwich simplifié de Bigwood et Crocombe est choisi comme outil de calculs de prédimensionnement de joints génériques, cependant une bonne connaissance des conditions limites est nécessaire. L’approche de simulation par la méthode des éléments finis en mécanique des milieux continus est alors recommandée. D’importantes difficultés de convergence des résultats des contraintes sont identifiées avec cette théorie, entre autres par la présence de singularités numériques aux interfaces du volume de l’adhésif. Des techniques de modélisation simplifiées, utilisant les outils du logiciel NX Nastran, sont ensuite testées et l’outil Surface-Gluing est alors proposé pour permettre la simulation de joints qui reflètent les caractéristiques de modélisation « industrielles » de Précicad. Finalement, une méthode de mesure des propriétés élastiques in situ pour adhésifs flexibles, compensée au moyen d’analyses par éléments finis, est développée afin de pouvoir réaliser une caractérisation avec un extensomètre conventionnel, tout en préservant la précision souhaitée. Ainsi, il a été possible d’isoler les modules de cisaillement et de tension de l’adhésif H8000.
This thesis initiates the development of a structural assessment method for aluminium adhesively bonded joints, intended for the industrial engineering businesses sector. The present work is devoted to the company Services Précicad inc, who needs design tools that can be used for its Kargo electric vehicle assemblies. In particular, the Taguchi design of experiment method is used to study the effects of joint conditioning on the static strength of different ASTM samples configurations. Commercially available products are screened out during the process. Thus, methacrylates is found to be the best adhesive chemical category for Précicad design and manufacturing needs. Subsequently, a review of different analytical models is carried and the Bigwood & Crocombe sandwich model is selected to perform a parametric analysis on the Single Lap Shear joint (SLS). The simplified version of the sandwich model was found to be the best suited for pre-sizing generic forms of adhesive joints, although a good knowledge of the boundary conditions is mandatory to make a realistic assessment. Consequently, the standard continuum mechanics finite element method is recommended for most joints analysis. However, major convergence difficulties can be found when using this theory, partly due to the presence of numerical singularities in the adhesive domain. Several simplefied modelling techniques using NX Nastran are tested on the SLS joint and the Surface-Gluing tool is proposed for evaluating complex “industrial” meshes such as the ones used by Precicad. Finally, a method for measuring in situ elastic properties of flexible adhesives with finite element analysis compensation is developed for achieving a complete characterization with a conventional clip gauge. Thus, it has been possible to measure the shear and tensile modulus of the H8000 adhesive.
This thesis initiates the development of a structural assessment method for aluminium adhesively bonded joints, intended for the industrial engineering businesses sector. The present work is devoted to the company Services Précicad inc, who needs design tools that can be used for its Kargo electric vehicle assemblies. In particular, the Taguchi design of experiment method is used to study the effects of joint conditioning on the static strength of different ASTM samples configurations. Commercially available products are screened out during the process. Thus, methacrylates is found to be the best adhesive chemical category for Précicad design and manufacturing needs. Subsequently, a review of different analytical models is carried and the Bigwood & Crocombe sandwich model is selected to perform a parametric analysis on the Single Lap Shear joint (SLS). The simplified version of the sandwich model was found to be the best suited for pre-sizing generic forms of adhesive joints, although a good knowledge of the boundary conditions is mandatory to make a realistic assessment. Consequently, the standard continuum mechanics finite element method is recommended for most joints analysis. However, major convergence difficulties can be found when using this theory, partly due to the presence of numerical singularities in the adhesive domain. Several simplefied modelling techniques using NX Nastran are tested on the SLS joint and the Surface-Gluing tool is proposed for evaluating complex “industrial” meshes such as the ones used by Precicad. Finally, a method for measuring in situ elastic properties of flexible adhesives with finite element analysis compensation is developed for achieving a complete characterization with a conventional clip gauge. Thus, it has been possible to measure the shear and tensile modulus of the H8000 adhesive.
Lefevre, Christophe. "Etude des propriétés structurales, magnétiques et électriques des solutions solides RMn6X6-xX'x (R=Gd-Lu, Sc, Y ; X=Ge, Sn ; X'=Ga, In) isotopes de HfFe6Ge6". Nancy 1, 2004. http://www.theses.fr/2004NAN10064.
Pełny tekst źródłaThis thesis reports on the structural, magnetic and electrical properties of pseudo-ternary RMn6X6-xX'x (R = Gd-Lu, Y, Sc ; X = Ge, Sn ; X' = Ga, In) isotypic with HfFe6Ge6. The determination of the atomic coordinates allows us to specify the crystalchemistry of these materials. We have thus shown that substitution occurs in the site which maintains the shortest R-Mn length. This work displays the dominating role of the valence electron concentration on the evolution of the magnetic properties of these compounds. We have specified the interactions model in the RMn6X6 compounds which seem to be governed by ferromagnetic interactions between first plane and by an antiferromagnetic interaction for the next one plane. Finally, the conductivity studies display anisotropic transport properties
Da, Ros Véronique. "Transport dans les composés thermoélectriques skutterudites de type R(x)Co(4-y)Ni(y)Sb(12) (R=Nd, Yb et In)". Thesis, Vandoeuvre-les-Nancy, INPL, 2008. http://www.theses.fr/2008INPL022N/document.
Pełny tekst źródłaIn a context of renewed interest in thermoelectric compounds, skutterudite materials are an interesting target because of their good performances in the temperature range 400-800 K. The study of structural and thermoelectric properties of cobalt triantimonides partially filled with neodymium, ytterbium and indium, and partially substituted with nickel, has been undertaken. Dense and homogeneous samples have been obtained using a powder metallurgy technique. The joint analysis of X-ray diffraction and electroprobe microanalysis led to the determination of the solubility limit of the filler elements: xNd ~ 0,05 – 0,06, and xYb ~ xIn ~ 0,18. For ytterbium, we were able to prove by powder neutron diffraction technique that the atoms are localized at the centre of the structure and that they have a very high atomic displacement parameter. Electrical properties (electrical resistivity, thermal conductivity, Hall effect) and thermal properties (thermal conductivity) have been investigated on a very large range of temperature (2 to 800K). The exploitation of the measurements showed that the higher the quantity of each insertion element, the greater its beneficial impact on the thermoelectric properties. The best performances have been reached with ZT ~ 0,3 for Nd0,052Co4Sb12 at 800 K, ZT ~ 0,9 in the case of In0,180Co4Sb12 at 710 K and ZT ~ 1 for Yb0,180Co4Sb12 at 800 K. An optimisation was considered using the partial substitution of cobalt by nickel. The impact of nickel on the thermoelectric performances on ternary compounds was very different depending on the element. In the case of neodymium, the presence of nickel modified the diffusion mechanism of the carriers and its impact was very beneficial. For indium and ytterbium, the impact of nickel did not lead to any significant improvement
Chen, Xiaolin. "Influence des ions aluminates sur la composition, la structure et les propriétés cohésives des hydrosilicates de calcium, constituants principaux de la pate de ciment Portland hydratée". Dijon, 2007. http://www.theses.fr/2007DIJOS072.
Pełny tekst źródłaPortland cement is mostly constituted of silicates and aluminates phases. When cement is hydrated, the main appearing component is calcium silicate hydrate (C-S-H) which results from the silicate phases hydration. The C-S-H is responsible for the cement paste setting. Aluminate phases after hydration, will produce the aluminate ions in the solution. It is well known that aluminate ions may substitute Si in C-S-H to form calcium alumino-silicate hydrate which is called C-S-A-H. This work aims to determine the effect of the Al/Si substitution on composition, structure and cohesion of C-S-H particles. C-S-H powders have been equilibrated in Ca3Al2O6 (C3A, one of cement components) hydration solutions in order to involve the Al/Si substitution in the solid. The analyses of the equilibrium solutions and solids show that C-S-A-H with tobermorite-like crystallographic structure and different Al/Si ratios have been obtained. AFM and electrokinetic investigations have been performed to describe the C-S-A-H/solution interface. An aluminum speciation on the solid has been achieved thanks to a new decomposition method of NMR 27Al spectra. By this method, we can distinguish and quantify each aluminum site in the solid and give a hypothesis of the structure based on tobermorite. With this structure, we have simulated the NMR 29Si spectra. These calculated spectra are in very good agreement with the experimental ones, which corroborates our C-S-A-H structure hypothesis. Finally, the overall quantitative analysis shows that the Al/Si ratio of C-S-H in a cement paste is around 0. 04
Agnel, Serge. "Mesures de charges d'espace dans les oxydes diélectriques par la méthode de l'onde thermique". Montpellier 2, 1996. http://www.theses.fr/1996MON20124.
Pełny tekst źródłaBoumediene, Mohamed. "Contribution des propriétés de surfaces réelles et de la nature du métal aux caractéristiques électriques des diodes Schottky, Au, Ag et In/n-GaP". Montpellier 2, 1990. http://www.theses.fr/1990MON20169.
Pełny tekst źródłaMasquelier, Nicolas. "Caractérisation et modélisation de transformations microstructurales pour la mise au point d'une nouvelle génération d'alliages d'aluminium pour conducteurs électriques". Rouen, 2012. http://www.theses.fr/2012ROUES011.
Pełny tekst źródłaNew aluminium alloy had been developed for electrical cable application. This alloy has good mechanical properties at high temperature, and also good electrical properties. Its microstructure had been characterized at atomic scale with the goal to link microstructure and physical properties. Thanks to this correlation, microstructure was adjusted to optimize the physical properties of this alloy. Microstructure of the alloy was also modelized to predict the evolution of physical properties with time. Finally, linking characterization and modelling, thermodynamical datas had been determined. These datas was unknown for this particular alloy and could be useful for the future
Lontsi, Fomena Mireille. "Etude théorique de la diffusion de l’oxygène dans des oxydes diélectriques". Thesis, Bordeaux 1, 2008. http://www.theses.fr/2008BOR13703/document.
Pełny tekst źródłaThe miniaturization of CMOS (Complementary Metal Oxide Semiconductor) components requires the use of high dielectric permittivity materials as gate oxide. LaAlO3 and SrTiO3 are among the best candidates, but the oxygen diffusion in these materials leads to the degradation of both the electrical properties and the interface with silicon. In this context, the aim of this theoretical work is to study the factors governing the oxygen ion diffusion at the chemical bonding scale. This approach is based on Density Functional Theory (DFT), coupled with electron density analysis methods, and the pioneering development of energy density cards. The regions of the electron density contributing to the diffusion barrier have been identified allowing new routes of optimization of these materials across the chemical bonding
Saad, Siham. "Nouveaux niobates, tantalates et antimoinates d'uranyle et de métaux alcalins". Thesis, Lille 1, 2008. http://www.theses.fr/2008LIL10090.
Pełny tekst źródłaThe work presented in this manuscript was dedicated to the synthesis and to the structural, electric and spectroscopic characterization of new compounds containing ion uranyl, transition metal oxoanions (Niobates, tantalates and antimonates) and alkaline metals. The first part of this study was devoted to the niobate family A1-xUNbO6-x/2, with x = 0 and 0,5 and A = alkaline; ln this family, the compounds can adopt two types of structural architectures: three-dimensional structures presenting large tunnels, or two-dimensional structures with a stacking of layers, where the monovalent cations are localized in the tunnels or between the layers. The role of the alkaline cation in the structural connectivity and dimensionality, as also in the stability of these phases, has been evidenced by carrying out various substitutions between alkaline cations: Cs1.- xKxUNbO6, CS0.5-xRbxUNbO5.75 and Cs1-xRbxUNbO6 or between oxoanions: CS0.5UNb1-xTixO5.75-x/2 and CS0.5UNb1-xWxOS.7S+x/2. The last part of that study was devoted to the alkaline uranyl tantalates and antimoinates. The structures of these new compounds AUMO6 (A = K et Cs; M = Ta, Sb) and A0,5UTaO5,75 (A = Rb, Cs) have been determined from powder X-Ray diffraction data
Tahri, Abdelali. "Propriétés électriques et réactivité du molybdate de nickel NiMoO4 synthétisé par réaction solide-solide : étude de la réduction (H2) et de la sulfuration (H2S/H2) par thermogravimétrie". Dijon, 1991. http://www.theses.fr/1991DIJOS018.
Pełny tekst źródłaAchargui, Nour-Eddine. "Elaboration de ZnSiAs2 par E. P. V. Et E. P. V. O. M : caractérisations optiques et électriques". Montpellier 2, 1991. http://www.theses.fr/1991MON20263.
Pełny tekst źródłaBelfarhi, Brahim. "Propriétés thermomécaniques des films minces utilises pour interconnecter les circuits intégrés : construction d'un appareil de mesure approprie, application à la caractérisation du nitrure de titane et à l’étude de la siliciuration du cobalt". Lyon, INSA, 1990. http://www.theses.fr/1990ISAL0105.
Pełny tekst źródłaThe fundamental mechanism knowledge of the thermo-mechanical behaviour of the interconnection metallic and dielectric thin films is needed to improve the integrated circuit fiability. The experimental anal sis of such a behaviour becomes possible if the stress developed in the film during a thermal treatment, defined by the phenomena to be studied, may be measured. When we start this study, we have to built a relevant equipment because none was available on the market. The different parts of our equipment are : a) a vacuum chamber in which the ten inch wafer is set, b) a twenty five kW rapid thermal annealing system made of twelve halogen lamps, c) an optical device able to rapidly measure, every twenty fifth second if necessary and precisely the wafer profile and curvature radius, d) at last a PC AT which drives the optical device and precisely control the wafer temperature according to a predefine set point law. The obtained results are then analysed using an other program. Our equipment allows us to show that : a) titanium nitride deposited on silicon by reaction of ammonia with titanium tetrachloride behaves as an elastic material, b) the orthorhombic silicide, resulting from the thermal interaction between silicon land cobalt, is stress free