Made available in DSpace on 2014-12-17T14:06:48Z (GMT). No. of bitstreams: 1 WersonMC.pdf: 1184207 bytes, checksum: f2f0598e463a68730749344c713c5bff (MD5) Previous issue date: 2008-02-22 / The Tungsten/copper composites are commonly used for electrical and thermal objectives like heat sinks and lectrical conductors, propitiating an excellent thermal and electrical conductivity. These properties are dependents of the composition, crystallite size and production process. The high energy milling of the powder of W-Cu produces an dispersion high and homogenization levels with crystallite size of W very small in the ductile Cu phase. This work discusses the effect of the HEM in preparation of the W-25Cu composite powders. Three techniques of powder preparation were utilized: milling the dry with powder of thick Cu, milling the dry with powder of fine Cu and milling the wet with powder of thick Cu. The form, size and composition of the particles of the powders milled were observed by scanning electron microscopy (SEM). The X-ray diffraction (XRD) was used to analyse the phases, lattice parameters, size and microstrain of the crystallite. The analyse of the crystalline structure of the W-25Cu powders milled made by Rietveld Method suggests the partial solid solubility of the constituent elements of the Cu in lattice of the W. This analyse shows too that the HEM produces the reduction high on the crystallite size and the increase in the lattice strain of both phases, this is more intense in the phase W / Os comp?sitos de Tungst?nio/Cobre (W-Cu) s?o geralmente usadas para fins el?tricos e t?rmicos como dissipadores de calor e condutores el?tricos, devido as suas excelentes propriedades de condutividades t?rmica e el?trica. Essas propriedades s?o dependentes da composi??o, do tamanho de cristalito e principalmente do processo de fabrica??o. A moagem de alta energia de p?s W-Cu produz alto n?vel de homogeneiza??o e dispers?o com cristalitos de W muito fino na fase d?ctil Cu. Este trabalho discute o efeito da MAE na prepara??o dos p?s comp?sitos W-25Cu. Tr?s t?cnicas de prepara??o dos p?s foram utilizadas: moagem a seco com p? de Cu grosso, moagem a seco com p? de Cu fino e moagem a ?mido com p? de Cu grosso. A forma, tamanho e a composi??o das part?culas dos p?s mo?dos foram observadas por microsc?pio eletr?nico de varredura (MEV). A difra??o de raios-X(DRX) foi usada para observar as fases, par?metros de rede, tamanho e microtens?o dos cristalitos. A an?lise da estrutura cristalina dos p?s mo?dos de W-25Cu feita pelo m?todo de Rietveld sugere uma solubilidade s?lida parcial dos elementos constituintes do cobre (Cu) na rede do tungst?nio (W). Essa an?lise tamb?m mostra que a MAE produz uma alta redu??o no tamanho dos cristalitos e um aumento de tens?o na rede de ambas as fases, isto ocorre com maior intensidade na fase do W

Made available in DSpace on 2014-12-17T14:07:22Z (GMT). No. of bitstreams: 1 AntonioCPS.pdf: 2085220 bytes, checksum: 8e64ae2c2f5ffe8a64dd3420c9c87327 (MD5) Previous issue date: 2007-03-23 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / In this work was used a plasma torch of non transferred arc with argon as work gas, using a power supply with maximum DC current of 250 A and voltage of 30 V to activate the plasma and keep it switched on. The flame temperature was characterized by optical emission spectroscopy, through Boltzmann-plot-method. The torch has been used like igniter in the aluminothermic reduction of the mixture tantalum oxide and aluminum, seeking to obtain metallic tantalum. In heating of the reagents only one particle will be considered to study interactions between plasma-particle, seeking to determinate its fusion and residence time. The early powders were characterized by laser granulometry, scanning electron microscopy (SEM) and X-ray diffraction analysis. The final product of this reaction was characterized by SEM and X-ray diffraction. Crystallite size was calculated by the Scherrer equation and microdeformation was determined using Willamsom-Hall graph. With Rietveld method was possible to quantify the percentile in weight of the products obtained in the aluminothermic reaction. Semi-quantitative chemical analysis (EDS) confirmed the presence of metallic tantalum and Al2O3 as products of the reduction. As was waited the particle size of the metallic tantalum produced, presents values in nanometric scale due the short cooling time of those particles during the process / Neste trabalho foi utilizada uma tocha de plasma de arco n?o transferido com arg?nio como g?s de trabalho, utilizando uma fonte de pot?ncia com corrente m?xima de 250 A e tens?o m?xima de sa?da de 30 V fornecida pelo fabricante. A temperatura da tocha foi caracterizada atrav?s da espectroscopia de emiss?o ?ptica, utilizando a curva de Boltzmann. A tocha foi usada como ignitor para a rea??o de redu??o aluminot?rmica do ?xido de t?ntalo mais alum?nio para a produ??o de t?ntalo met?lico. No aquecimento dos reagentes apenas uma part?cula ser? considerada para o estudo da intera??o tocha-part?cula, com o objetivo de determinar seu tempo de fus?o e resid?ncia. Os p?s de partida foram caracterizados atrav?s da granulometria a laser, microscopa eletr?nica de varredura (MEV) e difra??o de raios X. O produto final desta rea??o foi caracterizado por MEV e difra??o de raios X. O tamanho de cristalito foi calculado atrav?s da equa??o de Scherrer e a microdeforma??o foi determinada utilizando o gr?fico de Willamsom-Hall. Com o m?todo de Rietveld foi poss?vel quantificar o percentual em peso do produto da rea??o aluminot?rmica. An?lise qu?mica semiquantitativa (EDS) confirmou a presen?a do Ta met?lico e Al2O3 como produtos da redu??o. Como era de se esperar, o tamanho das part?culas do t?ntalo met?lico produzida apresenta valores na faixa de nan?metro devido pequeno tempo de resfriamento durante o processo

Ce travail est consacré à la synthèse de phases d’Hydroxydes Doubles Lamellaire (HDL) [NiAl-CO32-] à morphologies contrôlées et à l’étude de la relation entre leurs propriétés structurales / microstructurales et leurs propriétés électrochimiques. Les phases HDL sont préparées par un nouveau procédé de synthèse, basé sur un traitement hydrothermal en présence d’acides aminés. Nous avons mis en évidence l’influence de plusieurs paramètres de synthèse tels que la quantité d’acide aminé, la concentration de sels métalliques, le pH du milieu ainsi que la température et le temps du traitement hydrothermal ou encore la nature de l’acide aminé. Trois phases présentant différents degrés de cristallinité et différentes morphologies et représentatives des échantillons synthétisés, ont été plus particulièrement étudiées. Leur structure et microstructure ont été déterminées par affinement Rietveld en utilisant des données de diffraction des rayons X à haute résolution enregistrées au synchrotron. Ces résultats de DRX combinés avec les observations en microscopie électronique à transmission (MET) indiquent que l'élargissement des raies de diffraction 00l est principalement dû à des effets de taille, tandis que les effets, à la fois de taille et de micro-contrainte contribuent à l’élargissement anisotrope des autres réflexions hkl. Les micro-contraintes sont attribuées à un phénomène d’interstratification (CO32-/SO42-) et d’intercroissance de deux polytypes 2H1 et 3R1, confirmés et quantifiés à l’aide du logiciel DIFFaX. L’étude des propriétés électrochimiques de ces phases par voltammétrie cyclique a permis de montrer que la présence du motif d’empilement 2H1 induit une nette augmentation du signal électrochimique. / This work is devoted to the synthesis of NiAl-CO32- Layered Double Hydroxide phases (LDH) with controlled morphology and to the study of the relationship between the structural / microstructural and electrochemical properties. The LDH phases are prepared by a new synthetic method, based on the hydrothermal synthesis in presence of amino acids. We have highlighted the influence of various synthetic parameters such as the amount of amino acid, the concentration of metal salts, the pH of the medium, the temperature and time of hydrothermal treatment as well as the amino acid nature. Three phases of different degrees of crystallinity and different morphologies, representative of synthesized samples were particularly studied. Their structures and microstructures were determined by Rietveld refinement using high-resolution synchrotron powder X-ray diffraction (XRD) data. These XRD results combined with transmission electron microscopy (TEM) observations indicate that the broadening of 00l diffraction lines is mainly due to size effects, while both size and micro-strain effects contribute to the anisotropic broadening of the other hkl reflections. The micro-strain are attributed to an interstratification phenomena (CO32-/SO42-) and intergrowth between rhombohedral 3R1 and hexagonal 2H1 polytypes, confirmed and quantified using the software DIFFaX. The electrochemical properties of these phases are also studied by cyclic voltammetry showing that the presence of the 2H1 stacking motifs results in a net increase of the electrochemical signal.

[pt] A análise de sistemas de medição consiste do exame da adequação do sistema quanto ao operador, ao instrumento e a outras fontes de variação, bem como da comparação da variância do erro de medição com a variância natural do processo. Nesse aspecto, esta pesquisa teve por objetivo a análise das incertezas da quantificação de fase pelo método de Rietveld em análise de pó. Os efeitos de vários fatores na quantificação de fase foram avaliados utilizando técnicas estatísticas de planejamento experimental e de análise multivariada, com a utilização de materiais de alto nível de rastreabilidade na realização dos experimentos, no Laboratório de difração de raios X do Departamento de Ciências de Materiais e Metalurgia da PUC-Rio. Através da determinação do construto de variação do processo, constatou-se que a quantificação das fases analisadas sofre influência das condições de medição de forma diferenciada de material para material, impossibilitando a obtenção de uma fórmula geral para cálculo dos erros de quantificação, embora os erros possam ser determinados por uma análise de repetitividade e reprodutibilidade apropriadamente conduzida. / [en] The analysis of measurement systems is done by the examination of the adequacy of the system according to the operator, the instrument and other sources of variability, as well as by the comparison of the measurement error variance with the natural process variance. This research consisted in the evaluation of the uncertainties of phase quantification in powder analysis by the Rietveld method. The evaluation of the effects of several factors on the phase quantification was performed using statistical techniques of design of experiments and of multivariate analysis, with the use of materials of high level of traceability for the conduction of the experiments, in the Laboratory of X-ray Diffraction of the Pontifícia Universidade Católica do Rio de Janeiro. Through the determination of the variational structure of the process it was verified that the analyzed phases suffer influence of the measurement conditions in a differentiated way, which prevents the obtention of a general formula for calculation of the quantification error, although the errors can be determined by a repeatability and reproducibility analysis properly conducted.

Submitted by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2018-08-06T15:17:49Z No. of bitstreams: 1 DISSERTAÇÃO-Francisco Maciel de Brito Neto PPGCEM.pdf: 4657821 bytes, checksum: bfb975014ce10e6a646fdd1c54e9758b (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2018-08-06T15:18:13Z (GMT) No. of bitstreams: 1 DISSERTAÇÃO-Francisco Maciel de Brito Neto PPGCEM.pdf: 4657821 bytes, checksum: bfb975014ce10e6a646fdd1c54e9758b (MD5) / Made available in DSpace on 2018-08-06T15:18:13Z (GMT). No. of bitstreams: 1 DISSERTAÇÃO-Francisco Maciel de Brito Neto PPGCEM.pdf: 4657821 bytes, checksum: bfb975014ce10e6a646fdd1c54e9758b (MD5) Previous issue date: 2018-05-17 / CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico / Samples of samarium oxide (Sm2O3) and niobium oxide (Nb2O5) were submitted to Mechanical alloying technique and their structural evolution was accompanied by x-ray diffraction (XRD) measurements. In a few hours of milling SmNbO4 crystals were identified with two polymorphisms, one monoclinic and the other tetragonal. The diffractograms were simulated by Rietveld method and all crystallographic parameters were obtained, as well as the respective amounts of phases. The average crystallite sizes were estimated by the single-line method, indicating that both polymorphs have nanosized dimensions, that is, they are nanostructured. Combining calorimetric measurements, thermal treatments and x-ray diffraction the structural stability of the samples was studied. It was observed that the monoclinic structure undergoes phase transition to tetragonal structure in an exothermic process around 850 °C. The energy needed to promote the process was obtained by the Kissinger method and the XRD measurements indicate that the transition is irreversible. / Amostras de óxido de samário (Sm2O3) e óxido de nióbio (Nb2O5) foram submetidas à técnica moagem mecânica de alta energia e sua evolução estrutural foi acompanhada por medidas de difração de raios X (DRX). Em poucas horas de moagem foram identificados cristais de SmNbO4 com dois polimorfismos, um monoclínico e outro tetragonal. Os difratogramas foram simulados por método de Rietveld e todos os parâmetros cristalográficos foram obtidos, assim como as respectivas quantidades de fases. Os tamanhos médios de cristalitos foram estimados pelo método da linha única (single-line) indicando que ambos polimorfos possuem dimensões nanométricas, ou seja, são nanoestruturados. Combinando medidas calorimétricas, tratamentos térmicos e difração de raios x a estabilidade estrutural das amostras foi estudada. Foi observado que a estrutura monoclínica sofre transição de fase para estrutura tetragonal em um processo exotérmico em torno de 850°C. A energia necessária para promover o processo foi obtida pelo método de Kissinger e as medidas de DRX indicam que a transição é irreversível.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In this work we have studied the magnetic, optical and structural properties of ZnO nanoparticles pure and doped with different concentrations of Fe and Mn synthesized by three different synthesis methods; co-precipitation (CP), hydrothermal (SH) and thermal decomposition (DT). The samples were characterized by measurements of X-ray diffraction (XRD) and analyzed allied to Rietveld refinement method, absorption in the UV-Vis region, scanning and transmission electron microscopy (SEM and TEM), and magnetization measurements as a function of field and temperature (MvsH, MvsT). Through XRD analysis we have observed a dependence of the nanoparticle size with increasing temperature for both CP and SH methods well as a change in morphology with temperature for the samples system synthesized by SH. XRD analysis through the Williamson-Hall plot and TEM images show that particles obtained by SH and CP methods present an anisotropic growth, different of the particles obtained by DT method, that they present a spherical-like shape. The XRD results for Zn1-xFexO systems obtained by the CP and SH present only one phase but from point of view magnetic properties we have observed that these samples present transition at low temperature (T = 10 K) similar to an antiferromagnetic ordering. However, the Zn1-xFexO samples obtained by DT synthesis we have observed a paramagnetic behavior evidenced by MvsT curves. Therefore, at room temperature the MvsH curves indicated a ferromagnetic behavior. All Mn-doped ZnO samples present a paramagnetic behavior. The UV-Vis results show for all systems a slow increase in gap band with increases of dopant concentration. / Neste trabalho estudamos as propriedades magnéticas, ópticas e estruturais de nanopartículas de ZnO puras e dopadas com diferentes concentrações Fe e Mn sintetizadas por três diferentes métodos de síntese; co-precipitação (CP), hidrotérmico (SH) e decomposição térmica (DT). As amostras foram caracterizadas por medidas de difração de raios X (DRX) e analisadas juntamente ao método de refinamento Rietveld, absorção na região UV-Vis, microscopia eletrônica de varredura e de transmissão (MEV e MET) e medidas de magnetização em função do campo e da temperatura (MvsH, MvsT). Através das análises de DRX, nós temos observado uma dependência do tamanho da nanopartícula com o aumento da temperatura para ambos os métodos CP e SH, bem como uma variação na morfologia com a temperatura para o sistema de amostras sintetizado pela SH. Análises do gráfico de Williamson-Hall e imagens de MET mostram que as partículas obtidas através dos métodos SH e CP apresentam um crescimento anisotrópico, diferentemente das obtidas pelo método de DT, as quais apresentam morfologia esférica. Além disso, os resultados de DRX mostram que os sistemas Zn1-xFexO obtidos pela CP e SH apresentam somente uma fase, porém do ponto de vista das propriedades magnéticas observamos que as amostras apresentam uma transição em baixa temperatura (T = 10 K) similar a um ordenamento antiferromagnético. Por outro lado, as amostras de Zn1-xFexO obtidas pela síntese de DT observamos um comportamento paramagnético evidenciados pelas curvas de MvsT. No entanto, em temperatura ambiente as curvas de MvsH indicaram um comportamento ferromagnético. Todas as amostras de ZnO dopadas com Mn apresentam um comportamento típico de um material paramagnético. Resultados de absorção de UV-Vis para todos os sistemas estudados mostram um leve aumento na energia de gap com o aumento da concentração do dopante.

A qualidade óssea em grandes animais é avaliada pela densidade mineral óssea (DMO) utilizando a técnica de densitometria óptica em imagens radiográficas; o objetivo desse trabalho foi avaliar e comparar a qualidade óssea baseada na microarquitetura de uma forma inédita. Foram selecionados 20 bovinos, 10 da raça Canchim e 10 da raça Nelore, com controle dos processos biológicos e bioquímicos do nascimento até o abate aos 24 meses de idade, antes de entrarem na fase adulta. O osso metatarsal foi escolhido por suportar maior carga e amostras da diáfise do osso cortical seco foram obtidas. A avaliação da estrutura cristalina de ossos metatarsais secos foi realizada utilizando difração de raios X com a aplicação do método de refinamento de Rietveld, avaliando parâmetros de rede, tamanho de cristalito e microdeformação. A técnica de nanoindentação permitiu avaliar os módulos de elasticidade e valores de nanoindentação. A composição química razão cálcio e fósforo do material, resistência à deformação plástica, valores de microdureza, e imagens de microscopia eletrônica de varredura e microscopia óptica foram realizadas. A comparação entre os resultados das duas raças, Canchim e Nelore, dos valores de parâmetros de rede da estrutura cristalina da hidroxiapatita, tamanho de cristalito, microdeformações, relação cálcio e fósforo, microdurezas Vickers/Knoop, nanodureza Vickers e módulo de elasticidade indicaram que a qualidade óssea das raças Canchim e Nelore é estatisticamente semelhante para 30% dos parâmetros estudados e que para os demais 70% dos parâmetros estudados não há semelhança. / The bone quality in large animals is evaluated by bone mineral density (BMD) using the optical densitometry technique in radiographic images; The objective of this study was to evaluate and compare bone quality based on microarchitecture unpublished. Twenty bovines were selected, 10 from the Canchim breed and 10 from the Nelore breed, with control of the biological and biochemical processes from birth to slaughter at 24 months of age, before entering adulthood. The metatarsal bone was chosen because it supported higher load and samples of the diaphysis of the dry cortical bone were obtained. The evaluation of the crystalline structure of dry metatarsal bones was performed using X - ray diffraction with the application of the Rietveld refinement method, evaluating network parameters, crystallite size and microdeformation. The nanoindentation technique allowed to evaluate the modulus of elasticity and nanoindentation values. The chemical composition calcium and phosphorus ratio of the material, resistance to plastic deformation, values of microhardness, and scanning electron microscopy images and optical microscopy were performed. The comparison between the results of the two races, Canchim and Nelore, of the network parameter values of the hydroxyapatite crystal structure, crystallite size, microdeformations, calcium and phosphorus ratio, Vickers/Knoop microhardness, Vickers nanodness and modulus of elasticity indicated that Quality of the Canchim and Nelore races is statistically similar for 30% of the studied parameters and that for the ofter 70% of the studied parameters there is no similarity.

Cette thèse porte sur l’étude de la synthèse et des données thermodynamiques des clathrates intermétalliques du système Na-Si, qui sont des matériaux pertinents pour les applications thermoélectriques et qui sont les précurseurs pour de nouvelles formes de Si prometteuses pour des applications photovoltaïques et photoniques. Dans ce travail la formation de clathrates Na-Si a été étudiée in situ et ex situ sous haute pression et haute température. Un nombre de nouvelles formes de silicium a été observé en chauffant des clathrates sous vide. Sous pression inférieure à 3 GPa les clathrates ne se forment pas par l’interaction des éléments. A la place, le siliciure Na4Si4 se forme et reste stable jusqu’à la fusion. Au-dessus de 3 GPa, Na4Si4 formé au début du chauffage, réagit avec l’excès de Si et donne Na30Si136 (structure II) et ensuite, si Na30Si136 réagit avec l’excès de Si pour former Na8Si46 (structure I) au dessous de 7 GPa et le clathrate NaSi6 au-dessus de 7 GPa. Des expériences ont été réalisées en utilisant des cellules standard Paris-Edimbourg (enclumes opposées) jusqu'à 6 GPa et la presse multi-enclumes pour les pressions au-dessus de 6 GPa. La forte sensibilité des produits de cristallisation à la concentration en sodium a été observée. Un schéma de transformations de clathrate pour les pressions entre 0 à 10 GPa et températures entre 300 et 1500 K a été proposé. Le diagramme de phase (concentration – température sous 4 GPa) qui représente les transformations observées et les domaines de stabilité a également été proposé et suggère l’existence de trois équilibres eutectiques : entre Si et structure I, entre structures I et II, et entre structure II et Na4Si4. Pour comprendre la thermodynamique et les interactions dans le système Na-Si, on a également effectué la modélisation du diagramme de phase à pression ambiante, ce que nous a permis de trouver les caractéristiques thermodynamiques de fusion et les équations des liquidus observés. Pour prendre en compte l’impact de la pression sur la thermodynamique, les équations d’état p-V-T de Si à structure diamant, structure I et la forme haute pression de structure II ont été utilisés. / The objective of this thesis is to study the synthesis and thermodynamics of intermetallic clathrates of the Na-Si system, which are the important materials for thermoelectric applications and are the promising precursors for new forms of Si for the photovoltaic and photonic applications. In this work the formation of the Na-Si clathrates have been studied in situ and ex situ at high pressure and high temperature. A number of new forms of silicon have been observed while heating the clathrates under vacuum. Under pressures below 3 GPa the clathrates does not form by the interaction of elements. Instead, the silicide Na4Si4 forms and remains stable up to melting. Above 3 GPa, Na4Si4 formed in the beginning of the heating, react with the excess of Si and gives Na30Si136 (structure II) and after that, if Na30Si136 react with the excess of Si, to form Na8Si46 (structure I) below 7 GPa and the clathrate NaSi6 above 7 GPa. The experiments have been performed by using the standard Paris-Edinburg cell (opposite anvils) up to 6 GPa and multianvil press for pressures above 6 GPa. The strong sensibility of the crystallization product to the concentration of sodium has been observed. The diagram of transformations in clathrates for pressures between 0 and 10 GPa and temperatures between 300 and 1500 K has been proposed. The phase diagram (concentration – temparature at 4 GPa) that represents the observed transformations and stability domains has been also proposed and suggests the existence of three eutetic equilibria: between Si and structure I, between structures I and II, and between structure II and Na4Si4. To understand the thermodynamics and interactions in the system Na-Si, the modelisation of phase diagram at ambient pressure has also been performed that allowed us to establish the thermodynamic characteristics of melting and the equations of observed liquidi. To take into account the impact of pressure on the thermodynamics, the p-V-T equations of state of diamond Si, structure I and high-pressure form of structure II have been used.

La synthèse de matériaux zéolithiques est régie par de nombreux paramètres, en particulier la nature de l'hétéroélément associé au silicium et celle de l'agent organique structurant. Ainsi, l'introduction de germanium dans les milieux réactionnels ainsi que l'utilisation de structurants dérivés d'imidazole, les cations 1-éthyl-3-méthylimidazolium et 1-butyl-3-méthylimidazolium, ont permis la découverte de deux nouveaux solides microporeux nommés respectivement IM-16 et IM-20 et présentant des topologies de charpente inédites (respectivement UOS et UWY). De plus, un troisième germanosilicate poreux nommé IM-17 a été obtenu en présence du cation décaméthonium. Chacun de ces trois matériaux possède un système tridimensionnel de canaux avec des ouvertures de 8 et 10 atomes T (IM-16) ou de 10 et 12 atomes T (IM-17 et IM-20), ainsi que des unités de construction composites d4r au sein de leur charpente. Enfin, une partie importante du travail a été consacrée à l'élaboration de molécules structurantes originales (dérivés du décahydro-dicyclopenta[b,d]pyrrole) puis de leur emploi en synthèse hydrothermale. Ces essais ont permis d'obtenir divers matériaux déjà connus, parmi lesquels les zéolithes IM-12 (UTL), ITQ-7 (ISV), ITQ-17 (BEC) et ITQ-21. / The synthesis of zeolitic materials is ruled by numerous parameters, particularly the nature of the heteroelement associated with silicon and of the organic structure-directing agent (SDA). The introduction of germanium into the synthesis gels and the use of imidazole-derived SDAs, the cations 1-ethyl-3-methylimidazolium and 1-butyl-3-methylimidazolium, allowed us to discover two new microporous solids named IM-16 and IM-20 and exhibiting novel framework structures (respectively UOS and UWY). Furthermore, a third porous germanosilicate named IM-17 was obtained in the presence of the decamethonium cation. Each of these materials possesses a three-dimensional channel system with 8- and 10-ring pores (IM-16) or 10- and 12-ring pores (IM-17 and IM-20), as well as double-4-ring (d4r) composite building units in their framework. Finally, an important part of this work was dedicated to the elaboration of original SDAs (decahydro-dicyclopenta[b,d]pyrrole derivatives) and their use in hydrothermal synthesis. This led to the synthesis of several known zeolites such as IM-12 (UTL), ITQ-7 (ISV), ITQ-17 (BEC) and ITQ-21.

Synthèse et hydratation de la phase ye’elimite Les ciments riches en ye’elimite ou les ciments sulfoalumineux (CSA) sont commercialisés pour la préparation des bétons à compensation de retrait. De plus, les ciments CSA présentent des caractéristiques écologiques associées à leur production, notamment une réduction de l'empreinte CO2. Le comportement expansif des ciments CSA est principalement contrôlé par la quantité de la phase ettringite, cette dernière est produite lors de l’hydratation de la phase importante, la ye’elimite [Ca4 (Al6O12)SO4]. Cette thèse présente, d’une part, les conditions optimales pour la synthèse de la phase ye’elimite la plus pure possible par des réactions à l’état solide, et d’autre part, une description fondamentale des mécanismes de formation de cette phase. Un autre aspect de ce travail vise à étudier l’influence de la finesse et de l’addition d’acide citrique sur la dissolution de la phase ye’elimite. Pour l’étude de l’effet de la finesse, une poudre fine et pure de ye’elimite a été synthétisée par des méthodes sol-gel, ces dernières méthodes de synthèse ont été développées d’une manière originale dans notre thèse. Plusieurs techniques expérimentales ont été réalisées pour mener à bien les différents aspects de la présente thèse, à savoir l'analyse quantitative par DRX (méthode Rietveld), l’analyse thermique (ATG, ATD, et dilatométrie), MEB (imagerie en rétrodiffusé et cartographie EDS), l’analyse BET, l’analyse granulométrique par diffraction laser, et l’analyse d'images (porosité 2D et analyse granulométrique 2D). / A Synthesis and hydration of ye’elimite Ye’elimite-rich cements or calcium sulfoaluminate (CSA) cements are commercialized to prepare shrinkage compensation and self-stressing concretes. Moreover, CSA cements show environmentally friendly characteristics associated to their production, which include reduced CO2 footprint. The expansive behavior of CSA cements is mainly controlled by ettringite amount, produced upon hydration of the key-phase, ye’elimite [Ca4(Al6O12)SO4]. This work presents, on one hand, the optimal conditions for the synthesis highly pure ye’elimite by solid state reactions, and on the other hand, it shows a fundamental description of ye’elimite formation mechanisms. Another aspect of the study encompasses the influence of fineness and citric acid addition on ye’elimite phase dissolution, then on hydrates composition of lab made ye’elimite-rich cement. For the fineness effect study, a highly fine and pure ye’elimite was originally synthetized by sol-gel methods. Various experimental techniques were performed to conduct the different aspects of the present study, namely XRD-Quantitative Rietveld analysis, Thermal analysis (TGA, DTG, DTA and Dilatometry), SEM (BSE imaging and EDS mapping), BET analysis, PSD by laser diffraction, and Image analysis (2D porosity and 2D PSD).