Дисертації з теми "Verre de borosilicate"
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Poirot, Isabelle. "Etude du neptunium dans un verre borosilicate." Grenoble 2 : ANRT, 1986. http://catalogue.bnf.fr/ark:/12148/cb376004621.
Cachia, Jean-Nicolas. "Solubilité d'éléments aux degrés d'oxydation III et IV dans les verres de borosilicate." Montpellier 2, 2005. http://www.theses.fr/2005MON20165.
Bouteille, Barbara. "Séparation de phase dans les couches minces de verre pour la nanostructuration de surface." Electronic Thesis or Diss., Sorbonne université, 2020. http://www.theses.fr/2020SORUS249.
This work aims at creating nanostrcutures which size can be controlled from a planar glass thin film of 100~nm deposited by reactive magnetron sputtering, thanks to phase separation phenomenon. The model ternary system used is a barium borosilicate because its immicibility domain is large. After demixing the barium rich phase has strong electronic contrast favorable for SEM imaging. Moreover this less polymerized phase can be selectively dissolved to reveal nanostructures. Three different morphologies are finally obtained varying thin films composition : holes, pillars or interconnected roughness. Image processing from SEM and AFM measurements allows quantitative measurements of characteristic lengths such as vertical and horizontal size and lateral correlations. Coarsening kinetics in ultra-confined media are studied for both mechanisms nucleation and growth and spinodal decomposition. Particularly, for droplets assembly with only one object into the thickness, confinement slows down diffusion. This impact is shown experimentally and numerically, it gives a power law slower than classical models. For 2D interconnected network, hydrodynamic growth is quickly interrupted by fragmentation and destabilises the free surface leading to rough samples
Pacaud, Fabien. "Étude des propriétés physicochimiques de verres borosilicatés et de borosilicates de lanthane par dynamique moléculaire à partir d’un champ de force polarisable." Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066504/document.
As result of the nuclear waste vitrification, the knowledge and understanding of the dynamic and structural properties of glasses, including the behavior of radionuclides, is important (in liquid and solid phases). It can influence the glass waste properties, the lifetime of the vitrification process and the amount of radionuclides introduced in the glass matrix. Molecular dynamic simulations have been done to study the influence of the glass matrix composition into the structural and dynamic properties of the glass. A simplified glass, with 3 major oxides of the R7T7 glass such as SiO2, B2O3 and Na2O, have been used to simulate the R7T7 industrial nuclear glass (a 30 oxides glass). The inclusion of La2O3 allows us to simulate the impact of fission products and minor actinides into the properties of the glass matrix. Both systems, the SiO2-B2O3-Na2O and SiO2-B2O3-Na2O-La2O3, allow us to study the sodium and lanthanum effect on the properties of the glass. During this work, a polarizable force field has been developed to do these simulations. The results obtained at room temperature let us reproduce the experimental results of the structure, the distribution of BIII/BIV and the density. A study has been done on the viscosity and electrical conductivity of the liquid. The distribution BIV/BIII and the influence of the structural changes on the density along with the temperature have also been observed with thermal quenchings. The current limits of this approach are also described
Bouttes, David. "Micro-tomographie d’un borosilicate de baryum démixé : du mûrissement à la fragmentation." Thesis, Paris 6, 2014. http://www.theses.fr/2014PA066302/document.
We use a barium borosilicate glass as a model system to study phase separation in liquids. We consider here the coarsening process in the viscous hydrodynamical regime, where the characteristic length scale grows linearly with time : ∼ (γ/η)t, with η the viscosity and γ the interfacial tension. The system is initially bicontinuous, which is mandatory for this growth regime.X-ray microtomography experiments are performed in situ at the ID19 beamline of the European Synchrotron Radiation Facility (ESRF) in order to obtain the morphology of the domains. We developed dedicated image processing routines for the analysis of the 3D images. We computed the volumes and surface areas of the domains, chord-length distributions, the Euler characteristic as well as local mean and Gaussian curvatures. Dynamic scaling hypothesis predicts a self-similar growth, which served as a basis for the discussion of these measurements. The glass separates in two phases with a very high viscosity contrast (several orders of magnitude). The main control parameter in our experiments is then the volume fraction of the less viscous phase. When this low-viscosity phase is the minority one, it undergoes a gradual fragmentation that eventually stops the coarsening. This fragmentation process bears self-similar features, which result in a wide distribution of domains sizes. We indeed predict a power-law distribution. More generally, we observed that the coarsening process follows the dynamic scaling hypothesis as long as fragmentation remains insignificant
Pablo, Hélène. "Diffusion chimique dans les verres borosilicates d'intérêt nucléaire." Thesis, Paris, Muséum national d'histoire naturelle, 2017. http://www.theses.fr/2017MNHN0014/document.
Chemical diffusion is a key-phenomenon during nuclear glass synthesis. At high temperature, diffusion leads to homogenization of the melt contributing to the transformation of heterogeneous waste and frit precursors to a homogeneous glass after cooling. In contrast, in the supercooled liquid, diffusion is a critical factor affecting phase separation and/or crystallization processes that must be avoided when producing a high quality final product.In this manuscript, the impact of chemical diffusion on crystallization and liquid homogenization is studied for a simplified sodium borosilicate glass between its glass transition temperature and its synthesis temperature. For this kind of system, qualified as multicomponent, the description of diffusive phenomena requires the calculation of a diffusion matrix that takes into account diffusive couplings between species. These couplings can be written in the form of diffusive mechanisms or “diffusive exchanges” that are invariant with temperature. The activation energies associated with these exchanges are close to the activation energy of shear viscosity which suggests that viscous flow and chemical diffusion are driven by a single mechanism related to the frequency of Si-O and B-O bond breaking. It is also highlighted that in the supercooled liquid, the principal diffusive exchange (SiO2-Na2O) and the secondary diffusive exchange (SiO2-B2O3) play a significant role on the kinetics and direction of growth of crystalline phases which are formed in our system. These results are used to rationalise the evolution of compositional gradients in the vicinity and far from crystals. In the last part of this work, a complexification of the glasses was initiated by adding lanthanum to simulate one of the main lanthanides of the R7T7 nuclear glass composition. The data collected reveal diffusive couplings between lanthanum and silicon. These couplings, combined with the other results explain the formation of a lanthanum borosilicate phase (LaBSiO5)
Lizzi, Federico. "Phase separated borosilicate glasses for dental applications : mixture design in relation with the ion release in acid condition and microstructure." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSE1076/document.
The research for efficient dental materials has been a constant throughout the history of dentistry. As better materials emerged, the development of ever more innovative materials has been pushed forward. Moreover the combination of different sciences such as chemistry, biology, physics and engineering has provided better knowledge to the demanding requirements of the dental restorations. The BIODENSOL project is a European commission funded mobility research project managed by the University of Lyon and LUCIDEON Ltd, Stoke-on-Trent, UK. The project is designed to help building relations between academic and commercial research to enhance medical innovations and associates solid state chemists and hospital practicioners in direct contact with the patients with dental problems. This project proposes three PhD studies to address the problems of caries and enamel erosion by acidic foods (leading to sensitive teeth) encouraging re-mineralization to help avoid these problems. The researches independently evolved in three different routes investigating three different materials that could provide potential solutions. The main objective of this thesis concerns the study of Borosilicate phase separated glass powders for glass ionomer cements. As silicate bioglasses developed by Hench in 1969, regarding their bioactivity and antimicrobial properties, borosilicates glasses are promising materials and have been widely studied for biomedical applications for scaffolds in soft tissues and for bone repair and could be of interest in dentistry. The glass system studied here is a borosilicate glass (SiO2-K2O-B2O3-CaO-Al2O3) with a strong tendency to phase separate. The objective of this work is to characterize a series of the novel borosilicate formulations and to understand the mechanism and kinetic of dissolution related to their microstructure and composition. The use of thermal treatment to promote phase separation as a means of influencing the rate of ion leaching was especially studied. The dissolution process of borosilicates in neutral body solution (simulating body fluid) or in acid solution (simulating scenarios where bacteria or acid foods are present) provides information regarding the type and concentration of species released by the glass. Different compositions have been investigated in which SiO2 and K2O are fixed while the other elements are varied in order to assess the effect on the phase separation. As the novel borosilicates produced with the meltquenching technique is immersed in an aqueous environment, B-, Si-, Ca-, K- and Al- species are released to different degrees as a function of the time. Ion leaching trends can be related to the glass chemistry and microstructure. It has been shown that the amorphous phase separation (APS) causes an initially homogeneous single phase to separate into two or more phases of different compositions. The degree of interconnectivity of the two glass phases depend on the nature of the phase separation mechanism. This process can occur by a nucleation and growth process which gives isolated spherical particles or by spinodal decomposition where an interconnected structure is obtained. It is significant that before a heat-treatment the glasses are optically clear, but turn opalescent to different degrees following a heat treatment depending on the wt% of the elements in the composition. The pattern of the ion release implies that one of the phases is more reactive and susceptible to acid attack and will be leached out from the glass earlier. The other phase will remain in the cement improving the mechanical properties of the dental restorative material. Moreover, the mixing of the glass powder with a commercial poly(acrylic acid) has shown interesting mechanical and bioactive properties. This work showed how the ions leaching are influenced by the glass composition and the heat-treatment... [etc]
Jouglard, Dylan. "Propriétés électriques de verres d'intérêt nucléaire." Thesis, Orléans, 2018. http://www.theses.fr/2018ORLE2036/document.
The vitrification of high-level nuclear waste is an important step to master in order to ensure their immobilization. Since 2010, a cold crucible induction melter is used in the La Hague plant due to its advantages. This process is based on electromagnetic currents directly induced on the load of the crucible whose walls are water-cooled. Thanks to the thermal gradient established between these cooled walls and the molten glass, a solid glass layer called self-crucible is created which protects the crucible from corrosion effects and acts as an electrical insulator. Due to their complex composition and microstructure, the study of electrical and dielectric properties of nuclear glasses and the understanding of the related phenomena are necessary in order to efficiently master the cold crucible process and the associated thermo-hydraulic simulations.This study is dealing with the description of the electric charge motion phenomena involving the electrical and dielectric properties of the nuclear borosilicate glasses. Relationships between these properties, the composition and the microstructure are also given. These issues are firstly broached through the investigation of two industrial inactive glasses of complex composition thanks to microstructure characterizations and complex impedance measurements in the solid-state. A more detailed description of the phenomena is performed thanks to the characterization of simplified glasses containing 5 oxides (SiO2-B2O3-Na2O-CaO -RuO2 or -MoO3) allowing a better understanding of the charge motion according to the electrical field frequency, the temperature, the composition and the microstructure of the material
Diallo, Babacar. "Etude structurale des phénomènes de séparation de phases dans des verres d'oxydes aluminosilicatés et borosilicatés : application à la synthèse de vitrocéramiques." Thesis, Orléans, 2018. http://www.theses.fr/2018ORLE3014.
Phase separation phenomena in glasses correspond to the formation of heterogeneities during melting,quenching, or any other heat treatment. These heterogeneities modifies the homogeneity and thephysicochemical properties of glasses in the liquid state and can affect shaping operation of glasses. Thus,phase separation study is particularly interesting in the context of glasses formulation and glass-ceramicssynthesis. Indeed, the microstructures induced by the phase separation often lead to regularly distributedvitreous domains in a vitreous matrix, which can be crystallized under an appropriate heat treatment. So, thestructural modifications generated by the phase separation in ternary lanthanum aluminosilicate LaAS,lanthanum borosilicate LaBS and barium borosilicate BaBS is studied by using high resolution solid state NMRto understand the structural changes caused by the phase separation for glass ceramics synthesis
Hongisto, Mikko. "Développement de verres et vitrocéramiques dopés ytterbium pour l'optique et réponses sous différents types de traitements." Electronic Thesis or Diss., Bordeaux, 2024. http://www.theses.fr/2024BORD0040.
This thesis studies the modification of the properties of glass compounds doped with Yb3+ ions, through variations in composition, thermal or radiation treatments as well as by immersion in aqueous medium. New Yb3+ doped oxyfluorophosphate glass/glass-ceramics have been developed and characterized to obtain fundamental information on crystallization. The study also proposes the development of cylindrical and rectangular bioactive fibers based on doped and non-doped borosilicate glass constituting the core and the clad of the fiber respectively. The stability of these fibers in aqueous medium is monitored according to the geometry. This study also provides information on resistance to defects depending on the nature of the network and on the development of new bioactive fibers, the emission of which could be used to follow the dissolution of the fiber in aqueous medium. This study contributes to a better fundamental understanding of how composition changes and thermal/radiation processes can modulate the performance parameters of glass materials doped by Yb3+ ions
Mishchik, Konstantin. "Ultrafast laser-induced modification of optical glasses : a spectroscopy insight into the microscopic mechanisms." Phd thesis, Université Jean Monnet - Saint-Etienne, 2012. http://tel.archives-ouvertes.fr/tel-00966418.
Marc, Jean-Louis. "Elaboration et caractérisation optique de nano-cristallites semi-conductrices CdX (X = S, Se, Te) dispersées dans un verre borosilicate de sodium préparé par le procédé sol-gel." Montpellier 2, 1994. http://www.theses.fr/1994MON20257.
Barth, Nicolas. "Sur la modélisation et la simulation du comportement mécanique endommageable de verres borosilicatés sous sollicitation thermique." Thesis, Strasbourg, 2013. http://www.theses.fr/2013STRAD016/document.
We study the thermomechanical behavior of vitrified waste packages by multiphysics modeling. The packages are manufactured by the cast of borosilicate glass into stainless steel canisters. The finite element method is used for the thermal computations.In the glass, the finite element analysis is also used to compute the specific volume evolution and the viscoelastic behavior, due to the structural relaxation of glass, as well as the simulation of the damage behavior. These consecutive behavior laws model theinfluence of the initial thermal response. Glass structural relaxation is computed using the TNM-KAHRmodel, which allows us to take into account fundamental phenomena of the glass transition, depending on the results of experimental and simulated thermal treatments. For the solid glass within this relaxation process, the stress may locally increase beyond critical values. The viscoelastic structure simulation is then coupled with continuum damage mechanics where stresses and stiffness are updated in mode I and mode II. We apply this simulation protocol after adopting conditions relative to the case of these manufactured bulky solidifying glass casts. The models then allow us to quantify the cracking surfaces inside the glass fromthe energy dissipated within the damagemodel
Fournier-Renaud, Judith. "Cinétiques de dissolution des cristaux dans les silicates fondus : contexte des verres nucléaires." Thesis, Montpellier, 2017. http://www.theses.fr/2017MONTS034/document.
In France, High-Level radioactive Wastes (HLW) coming from nuclear spent fuel treatment are confined at the atomic scale in an homogeneous sodium-borosilicate glass called the R7T7 glass. At different stages of the melting process performed at high temperature, crystallized phases which incorporate the radionuclides are temporarily formed before their dissolution. The formation conditions of these crystals have already been studied but, to date, few studies on their dissolution in nuclear glass melt have been performed. The objective of this thesis is the description of the kinetics and mechanisms of the crystals dissolution in the borosilicate melt.This study focuses on the dissolution of rare earth silicates with an apatite structure (Ca2Nd8(SiO4)6O2 type) in three borosilicate melt compositions. Experiments are conducted in isothermal mode and in closed system. The crystalline fractions are followed according to time thanks to the acquisition of SEM images mosaics coupled with image analysis. In addition, chemical profiles at the crystal/melt interfaces are acquired by microprobe.The Johnson-Mehl-Avrami-Kolmogorov (JMAK) model, usually applied to describe the crystallization in melt, is successfully applied to the crystalline fractions measured during the dissolution process. The application of this model for different temperatures of thermal treatment validates its effectiveness to describe the dissolution kinetics of rare earth silicates in borosilicate systems in static mode. Its application is furthermore extended to the crystals dissolution in more complex systems where different types of crystals are simultaneously present. This model allows to determine the mechanism limiting the crystals dissolution in borosilicate melts, i.e. the diffusion in the studied systems, the activation energy of the dissolution as well as the constants of dissolution and the characteristic durations of dissolution for each considered temperature
Bisbrouck, Nicolas. "Influence du magnésium sur la structure et l'altération aqueuse de verres borosilicatés : application aux verres de type AVM." Thesis, Université de Montpellier (2022-….), 2022. http://www.theses.fr/2022UMONS008.
As part of AVM nuclear glasses, magnesium can susbtancially impact both their structure and chemical durability when compared to R7T7 type glasses. It is therefore necessary, for deep geological repository purposes, to gain insights in identifying, understanding and quantifying these effects. As such, this study focuses on an aluminoborosilicate glass series with varying magnesium content, in which a reference AVM glass (AVMV4) and a derived composition based on its five main oxides are found. An extensive structural study through multinuclear solid-state NMR, Raman spectroscopy and neutron diffraction was performed: it revealed that magnesium drastically decreased boron mean coordination, more sharply than calcium, and tends to favour boron interconnection through boroxol rings. Increasing magnesium content highligthed its poor ability to compensate for tetrahedral aluminium units, and could lead to the formation of two subnetworks through the formation of Mg--Na mixing sites. Additionaly, high alkali concentration appears to lead to a decrease in magnesium mean coordination. Comparison between the structural features of the AVMV4 glass and its simpler counterpart revealed a high degree of similarity. Molecular dynamics simulations were found to qualitatively well reproduce the glasses structure, namely the decrease in boron coordination with increasing magnesium content, amongst others. It also revealed that increasing magnesium content in the glass series tends to increase the coordination distribution of magnesium, which centers around a mean value of five. Data obtained from topological constraints enumeration highlighted a more organised angular environment of magnesium with its first neighbours than what was observed for calcium. Additionaly, an intermediate behaviour, between network-formers and modifiers was suggested for magnesium atoms when in presence of a high alkali concentration, displaying a more organised environment, as also suggested by experimental data. Finally, leaching experiments performed at pH(90°C)= 9 et T = 90°C indicates that magnesium in the glass composition decreases the initial dissolution rate by a factor of two compared to an equivalent calcium--containing glass. The nuclear glass and its derived simplified composition displayed similar dissolution rates, making the simple glass a good analogue in the initial dissolution regime. Increasing magnesium content in the glass series lead to an increase in initial dissolution rate, displaying similarities in behaviour with network forming species such as aluminium. Finally, limitations of current structural descriptor--based models to link structural modifications to glass aqueous reactivity was discussed
Rehouma, Ferhat. "Étude de l'échange d'ions a l'argent dans un verre aluminoborosilicate : application a un procède d'enterrage sélectif des guides." Grenoble INPG, 1994. http://www.theses.fr/1994INPG0093.
Linard, Yannick. "Thermochimie des verres borosilicates. Contribution a l'etude de l'alteration des verres de confinement de dechets radioactifs." Paris 7, 2000. http://www.theses.fr/2000PA077138.
Adjanor, Gilles. "Modélisation thermodynamique des verres nucléaires : coexistence entre phases amorphes." Paris 11, 2006. http://www.theses.fr/2006PA112285.
Investigating the stability of borosilicate glasses used in the nuclear industry with respect to phase separation requires to estimate the Gibbs free energies of the various phases appearing in the material. In simulation, using current computational resources, a direct state-sampling of a glassy system with respect to its ensemble statistics is not ergodic and the estimated ensemble averages are not reliable. Our approach consists in generating, at a given cooling rate, a serie of quenches, or paths connecting states of the liquid to states of the glass, and then in taking into account the probability to generate the paths leading to the different glassy states in ensembles averages. In this way, we introduce a path ensemble formalism and calculate a Landau free energy associated to a glassy metabasin. This method was validated by accurately mapping the free energy landscape of a 38-atom glassy cluster. We then applied this approach to the calculation of the Gibbs free energies of binary amorphous Lennard-Jones alloys, and checked the correlation between the observed tendencies to order or to phase separate and the computed Gibbs free energies. We finally computed the driving force to phase separation in a simplified three-oxide nuclear glass modeled by a Born-Mayer-Huggins potential that includes a three-body term, and we compared the estimated quantities to the available experimental data
Molières, Estelle. "Effet des terres rares sur la structure et l’altération des verres borosilicatés." Paris 6, 2012. http://www.theses.fr/2012PA066254.
This work is related to the question of the geological deep repsitory of high-level waste glass. These wastes include fission products and minor actinides, elements which can be simulated by rare earths. As new glass compositions could enable increased rare earth concentrations, it is crucial to know and understand rare earth impact on glass structure on the one hand, and on glass alteration kinetics or their incorporation into an altered layer. This work studied simplified borosilicate glasses in order to limit synergetic effects between rare earths and other elements. Various complementary techniques were used to characterize pristine and altered glasses (solid-high resolution NMR, Raman spectroscopy, fluorescence, SIMS, SAXS). Firstly, the structural role of a rare earth is discussed and is compared to a calcium cation. The local environment of rare earths is also probed. Secondly, rare earth (nature and concentration) impact on several alteration regimes was studied (initial rate, rate drop). Then, after alteration, rare earth elements being retained within the altered layer, the structural impact of rare earth elements (and their local environment) in this alteration layer was also investigated
Hélie, David. "Micro-usinage de lamelles de verre au laser femtoseconde." Thesis, Université Laval, 2011. http://www.theses.ulaval.ca/2011/28184/28184.pdf.
Cachia, Jean-Nicolas. "Solubilité d'éléments aux degrés d'oxydation III et IV dans les verres de borosilicate : application aux actinides dans les verres nucléaires /." [Gif-sur-Yvette] : [CEA Saclay, Direction des systèmes d'information], 2006. http://catalogue.bnf.fr/ark:/12148/cb409352592.
Molières, Estelle. "Effet des terres rares sur la structure et l'altération des verres borosilicatés." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2012. http://tel.archives-ouvertes.fr/tel-00735794.
Ledieu, Aurélien. "Altération par l'eau des verres borosilicatés : expériences, modélisation et simulations Monte Carlo." Phd thesis, Ecole Polytechnique X, 2004. http://tel.archives-ouvertes.fr/tel-00008627.
entre experiences et simulations num´eriques. Ils s'inscrivent plus generalement dans la problematique du comportement a long terme des verres de confinement des dechets nucleaires.
Dans un premier temps, nous avons etudie des verres contenant uniquement un melange d'oxydes de silicium, de bore et de sodium. Les cinetiques d'alteration montrent que la vitesse et le degre final de l'alteration dependent de la teneur initiale en bore selon un mecanisme de percolation. Il a ete observe qu'une pellicule se forme a la surface du verre et que, pour certaines compositions, celle-ci est responsable d'un arret de l'extraction des especes solubles (bore et sodium). Ce < gel d'alteration > est caracterise par resonance magnetique nucleaire (RMN) et diffusion des rayons X aux petits angles (SAXS).
D'autres elements ont ensuite ete ajoute a la composition borosilicatee initiale. Nous montrons ainsi que la presence d'oxydes de calcium, de zirconium et d'aluminium perturbe
fortement la vitesse et le degre final d'alteration et qu'il n'est plus possible d'interpreter le comportement de ces verres par la seule percolation du bore. En parallele, nous avons developpe un modele theorique, base sur la dissolution-recondensation des especes peu solubles, pour decrire l'alteration par l'eau des verres borosilicates. L'utilisation de simulations num´eriques de type Monte Carlo sur reseau teste
les concepts de percolation du sous-reseau de bore, de reactivite locale des elements peu solubles, ainsi que de murissement de la texture poreuse du gel. Ce modele est valide explicitement
sur les verres a trois oxydes (Si, B et Na) par confrontation directe avec les experiences. Il est ensuite etendu au cas des verres de composition plus complexe (verres au zirconium et a l'aluminium). Au moyen d'hypotheses simples, nous parvenons alors a interpreter qualitativement le comportement paradoxal de ces verres a quatre oxydes.
Ces travaux montrent principalement qu'il est possible d'expliquer le comportement en presence d'eau d'un verre de composition donnee par la competition entre deux mecanismes
primordiaux, qui sont l'extraction des elements solubles et la reconstruction du gel d'alteration.
Trotignon, Laurent. "La corrosion aqueuse des verres borosilicatés : nature et propriétés des couches d'altération." Toulouse 3, 1990. http://www.theses.fr/1990TOU30072.
Ledieu, Aurélien. "Altération par l'eau des verres borosilicatés : expériences, modélisation et simulations Monte-Carlo /." [Gif-sur-Yvette] : [CEA Saclay, Direction des systèmes d'information], 2005. http://catalogue.bnf.fr/ark:/12148/cb39964770g.
La couv. porte en plus : "Direction de l'énergie nucléaire" Bibliogr. p. 165-170. Résumé en français et en anglais.
Debure, Mathieu. "Étude de la dissolution de verres borosilicatés en présence de minéraux magnésiens modèles représentatifs des minéraux de l'argilite du Callovo-Oxfordien." Phd thesis, Ecole Nationale Supérieure des Mines de Paris, 2012. http://pastel.archives-ouvertes.fr/pastel-00797458.
Cailleteau, Céline. "Influence de la morphologie du gel sur la cinétique d'altération des verres borosilicates : rôle du calcium et du zirconium." Palaiseau, Ecole polytechnique, 2008. http://www.theses.fr/2008EPXX0044.
Collin, Marie. "Géochimie en milieu nanoporeux : application aux verres nucléaires." Thesis, Montpellier, 2018. http://www.theses.fr/2018MONTS066.
This work aims at understanding water interactions with the altered layer, called gel, formed during borosilicate nuclear glass corrosion. Specifically, we focus on the corrosion of the six oxides ISG. To better understand gel formation mechanisms, as well as gel passivating properties, experimental studies are combined to molecular dynamics simulations.First, this study focuses on the characterization of the pristine glass structure. Experimental analysis (NMR) provides some information to validate the simulated structure. As a result, an improved understanding of the pristine glass short- and medium-range orders is obtained. We also observe that network formers are homogeneously distributed, with no area enriched in boron for instance. Boron is known to be highly soluble, and tends to divide the silicate network, which would affect its reactivity.The gel formation is then studied experimentally in conditions favoring the passivating effect of the glass (90 °C, pH 7, silica-saturated solution). A strong effect of exogenous elements in solution, particularly weakly hydrated alkalis such as potassium and cesium, is observed, with a notable decrease of glass corrosion. To better understand this effect, all gels are characterized. A congruent release of boron and sodium is observed, while potassium and cesium are incorporated. They then act as charge compensator for [AlO4]- units. Calcium usually plays this role in gels formed in solutions with no alkali or containing strongly hydrated alkali such as lithium and sodium. The hydration degree differs for the various gels present, as confirmed by MD simulation of water diffusion in nanoporous amorphous silica in presence of alkali. These simulations highlight a combined impact of sterical effects (alkali size) and physicochemical effects (hydration energy) leading to a decrease of water quantity in the nanopores containing potassium and cesium.Moreover, all the gels formed in the above mentioned leaching conditions are highly polymerized, which indicates a reorganization of the network following the leaching of hydrolysable species such as boron. This reorganization happens without complete hydrolysis of silicon atoms, which invalidate the congruent dissolution/precipitation model in this case. Water speciation inside the gel is determined combining TGA and NMR, giving access to quantitative oxygen repartition in the gel (bridging oxygen, non-bridging oxygen or H2O).This data are then used for the interpretation of tracing experiments carried out in H218O rich solution on prealtered samples. The results demonstrate for the first time that the network reorganizes continuously over time, with a decrease of mobile species (H2O and hydroxyls) accessibility due to the maturation of the porosity within the gel. We determine various water diffusivities as a function of the gel topology and propose the hypothesis that this decreasing reactivity of the network is the source of the passivating nature of the gel
Delorme, Ludovic. "Mecanismes de volatilite des verres et des fontes borosilicates d'interet nucleaire - influence de la structure." Orléans, 1998. http://www.theses.fr/1998ORLE2006.
Magnin, Magali. "Etude des processus de démixtion et de cristallisation au sein de liquides fondus borosilicatés riches en oxyde de molybdène." Paris 6, 2009. http://www.theses.fr/2009PA066502.
Jabobker, Khalid. "Etude de la photoconductivité de l'oxyde PbO dans les verres borosilicates obtenus par procédé sol-gel." Grenoble 2 : ANRT, 1988. http://catalogue.bnf.fr/ark:/12148/cb376144208.
Nicoleau, Elodie. "Impact de la cristallisation sur la structure et la durabilité chimique de verres borosilicatés." Thesis, Montpellier, 2016. http://www.theses.fr/2016MONTT274/document.
This work describes a new approach to help understand the chemical durability of partially crystallized nuclear waste conditioning matrices. Among the studies carried out on nuclear waste deep geological disposal, long-term behavior studies have so far been conducted on homogeneous glassy matrices. However, as the crystalline phases may generate modifications in the chemical composition and properties of such matrices, the description and a better understanding of their effects on the chemical durability of waste packages are of primary importance.A protocol to study the durability of heterogeneous model matrices of nuclear interest containing different types of crystalline phases was developed. It is based on a detailed description of the morphology, microstructure and structure of the glassy matrix and crystalline phases, and on the study of various alteration regimes. Three crystal phases that may form when higher concentrations of waste are immobilized in Uranium Oxide type conditioning glasses were studied: alkali and alkaline earth molybdates, rare earth silicates and ruthenium oxide.The results highlight the roles of the composition and the structure of the surrounding glassy matrix as the parameters piloting the alteration kinetics of the partially crystallized glassy matrices. This behavior is identical whatever the nature of the crystalline phases, as long as these phases do not lead to a composition gradient and do not percolate within the glassy matrix. Given these results, a methodology to study partially crystallized matrices with no composition gradient is then suggested. Its key development lies firstly in the evaluation of the behavior of partially crystallized matrices through the experimental study of the residual glassy matrix in various alteration regimes. This methodology may be adapted to the case of new glass formulations with more complex compositions (e.g. highly waste-loaded glass), which may contain crystals formed during cooling
Lopez, Christophe. "Solubilité des actinides et de leurs simulants dans les verres nucléaires : limites d'incorporation et compréhension des mécanismes." Paris 11, 2002. http://www.theses.fr/2002PA112218.
The nuclear wastes are currently incorporated in borosilicate glass matrices. The resulting glass must be perfectly homogeneous. The work discussed here is a study of actinide (thorium and plutonium) solubility in borosificate glass, undertaken to assess the extent of actinide solubility in the glass and to understand the mechanisms controlling actinide solubilization. Glass specimens containing actinide surrogates were used to prepare and optimize the fabrication of radioactive glass samples. These preliminary studies revealed that actinide surrogates solubility in the glass was enhanced by controlling the processing temperature, the dissolution kinetic of the surrogate precursors, the glass composition and the oxidizing versus reducing conditions. The actinide solubility was investigated in the borosilicate glass. The evolution of thorium solubility in borosilicate glass was determined for temperatures ranging from 1200ʿC to 1400ʿC. Borosilicate glass specimens containing plutonium were fabricated. The experimental result showed that the plutonium solubility limit ranged from 1 to 2. 5 wt% PuO2 at 1200ʿC. A structural approach based on the determination of the local structure around actinides and their surrogates by EXAFS spectroscopy was used to determine their structural role in the glass and the nature of their bonding with the vitreous network. This approach revealed a correlation between the length of these bonds and the solubility of the actinides and their surrogates
Cochain, Benjamin. "Cinétique et mécanismes d’oxydoréduction dans les silicates fondus : études expérimentales de verres nucléaires simplifiés et d’échantillons naturels." Paris 6, 2009. https://tel.archives-ouvertes.fr/tel-00813321.
This work contributes to better understand iron redox reactions and mechanisms in silicate melts. It was conducted on compositions in both Na2O-B2O3-SiO2-FeO et Na2OAl2O3- SiO2-FeO systems. The influence of boron-sodium and aluminum-sodium substitutions and iron content on properties and structure of glasses and on the iron redox kinetics has been studied by Raman, Mössbauer and XANES spectroscopies at the B and Fe K-edges. In borosilicate glasses, an increase in iron content or in the Fe3+/Fe redox state implies a structural rearrangement of the BO4 species in the glass network whereas the BO3 and BO4 relative proportions remain nearly constant. In all studied glasses and melts, Fe3+ is a network former in tetrahedral coordination, unless for aluminosilicates of ratio Al/Na>1 where Fe3+ is a network modifier in five-fold coordination. Near Tg, diffusion of network modifying cations controls the iron redox kinetics along with a flux of electron holes. At liquidus temperatures, oxygen diffusion is considered to be the mechanism that governs redox reactions. This study shows the role played by the silicate network polymerization on the redox kinetics. In borosilicate melts, iron redox kinetics depends on the boron speciation between BO3 and BO4 that depends itself on the sodium content. Furthermore, an increase in the network-former/network-modifier ratio implies a decrease in oxygen diffusion that results in a slowing down of the redox kinetics. The obtained results allow a description of the iron redox kinetics for more complex compositions as natural lavas or nuclear waste model glasses
Fournier, Maxime. "Etude des mécanismes à l’origine des reprises d’altération : Modélisation et impact sur les verres de confinement." Thesis, Montpellier, 2015. http://www.theses.fr/2015MONTS194/document.
A sudden and still poorly understood phenomenon, the resumption of alteration results in a sudden acceleration of the glass alteration rate due to the destabilization of the amorphous passivating layer formed on the glass surface. Understanding the origin and the consequences of this phenomenon is a major issue for the prediction of nuclear glass long-term behavior.This study quantitatively links the alteration degree of a six-oxide reference glass and the formation mechanisms of zeolites and C-S-H that control the solution chemistry. The role played by the decrease in aluminum concentration as an indicator of resumption is highlighted. It appears that the resumption occurrence and rate are correlated to the couple (T, pH), but even in the most adverse situations the resumption rate is lower than the initial alteration rate, which remains the fastest kinetic regime. Previously limited to alkaline pH, the characterization of alteration resumptions was extended to conditions more representative of those found in a geological repository. This approach required the development of a new tool: seeding, that reduces or eliminates the latency period preceding a resumption. The results obtained demonstrate its usefulness in understanding the role of zeolites in amorphous layer destabilization and for modeling alteration resumptions.A geochemical modeling approach to alteration resumption is proposed, based on the formalism of the GRAAL glass alteration model. It is based on the calculation of zeolite thermodynamic constants, on the implementation of their nucleation and growth kinetics, and on assumptions related to the solubility of the amorphous layer. When zeolite precipitation consumes alkali, glass alteration—driven by zeolite precipitation—releases alkali. The model highlights the importance of such chemical couplings and shows that, in the stoichiometry of French nuclear reference glass, their cumulative effects are the cause of a pH decrease which limits zeolite precipitation
Dietrich, Markus. "Etude du bullage de verres sodo-calciques et borosilicates fondus au contact de refractaires base cr#2o#3." Orléans, 1998. http://www.theses.fr/1998ORLE2037.
Barth, Nicolas, and Nicolas Barth. "Sur la modélisation et la simulation du comportement mécanique endommageable de verres borosilicatés sous sollicitation thermique." Phd thesis, Université de Strasbourg, 2013. http://tel.archives-ouvertes.fr/tel-00992971.
Kieu, Le Hai. "Compréhension de l'origine de l'évolution sous irradiations de la ténacité des verres nucléaires." Phd thesis, Ecole Polytechnique X, 2011. http://pastel.archives-ouvertes.fr/pastel-00660352.
Kayi-Maoumoucka, Jean-Claude. "Elaboration par procédé sol-gel et caractérisation de vitrocéramiques borogermanate et borosilicate contenant des semi-conducteurs (PbO, CdO, CdS)." Montpellier 2, 1991. http://www.theses.fr/1991MON20009.
Cochain, Benjamin. "Cinétique et mécanismes d'oxydoréduction dans les silicates fondus Études expérimentales de verres nucléaires simplifiés et d'échantillons naturels." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2009. http://tel.archives-ouvertes.fr/tel-00813321.
Mougnaud, Sarah. "Effets de l’irradiation sur l’évolution de la pellicule d’altération formée lors de la lixiviation des verres borosilicatés nucléaires." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLS322/document.
High-level radioactive waste (HLW) remaining after spent nuclear fuel reprocessing is immobilized within a glass matrix, eventually destined for geological disposal. Water intrusion into the repository is expected after several thousand years. The alteration of a non-radioactive surrogate for nuclear glass has been extensively studied and it has been determined that successive leaching mechanisms lead to the formation of a “passivating” alteration layer and to the establishment of a residual rate regime in the long term. However, glass packages are submitted to the radioactivity of confined radioelements. This work focuses on the influence of irradiation on the alteration layer formed during the residual rate regime, in a structural and mechanistic point of view. Three focal areas have been selected. Non-radioactive simple glasses have been leached and externally irradiated in order to determine modifications induced by electronic effects (irradiations with electrons and alpha particles). The same type of glass samples have been previously irradiated with heavy ions and their leaching behavior have been studied in order to assess the impact of ballistic dose cumulated by the glass before water intrusion. Leaching behavior of a complex radioactive glass, doped with an alpha-emitter, has been studied to consider a more realistic situation
Bonfils, Julien de. "Effets d'irradiations sur la structure de verres borosilicates : comportement à long terme des matrices vitreuses de stockage des déchets nucléaires." Lyon 1, 2007. http://tel.archives-ouvertes.fr/docs/00/17/72/41/PDF/Manuscrit_these_Julien_de_Bonfils.pdf.
This work deals with the long term behaviour of R7T7-type nuclear waste glasses and more particularly of non-active borosilicated glasses made up of 3 or 5 oxides. Radioactivity of active glasses is simulated by multienergies ions implantations which reproduce the same defects. The damages due to the alpha particles are simulated by helium ions implantations and those corresponding to the recoil nucleus are obtained with gold ions ones. Minor actinides, stemming from the used fuel, is simulated by trivalent rare-earths (Eu3+ and Nd3+) In a first part, we have shown by macroscopic experiments (Vickers hardness - swelling) and optical spectroscopies (Raman - ATR-IR) that the structure of the glassy matrixes is modified under implantations until a dose of 2,3. 1013 at. Cm-2, which corresponds to a R7T7 storage time estimated at 300 years. Beyond this dose, no additional modifications have been observed. The second part concerns the local environment of the rare-earth ions in glasses. Two different environments were found and identified as follows: one is a silicate rich one and the other is attributed to a borate rich one
Petit-Maire, Denis. "Structure locale autour d'actinides et d'elements nucleants dans des verres borosilicates d'interet nucleaire : resultats de spectroscopie d'absorption des rayons x." Paris 6, 1988. http://www.theses.fr/1988PA066474.
Petit-Maire, Denis. "Structure locale autour d'actinides et d'éléments nucléants dans des verres borosilicates d'intérêt nucléaire résultats de spectroscopie d'absorption des rayons X /." Grenoble 2 : ANRT, 1988. http://catalogue.bnf.fr/ark:/12148/cb376174382.
Marcq, Benoît. "Contribution à l' étude de l'environnement du nickel dans les verres silicatés : influence de la composition et des processus de réduction." Paris, Institut de physique du globe, 2004. http://www.theses.fr/2004GLOB0008.
Nickel is of significant interest within the framework of Earth and Materials sciences. Two structural studies, carried out using optical and X-ray absorption spectroscopies, were simultaneously undertaken. The first one, on borosilicate glasses, use Ni2+ as a probe of glass local structure. This study made it possible to highlight the evolution of relations between borate and silicate sub-networks, according to alkaly content. In the second study, reduction experiments were carried out on a glass simulating a basaltic composition in order to follow the evolution of glass local structure around Ni2+ during reduction. Indeed, metal-silicate reactions are key processes for comprehension of pre-terrestrial differentiation. Nickel oxidation state under these reducing conditions, necessary to determine metal/silicate partition coefficient, is thus discussed
Hansen, Erik. "Étude de l'incorporation de fer, nickel et chrome dans les verres de conditionnement de déchets nucléaires." Electronic Thesis or Diss., Université de Lorraine, 2022. http://www.theses.fr/2022LORR0349.
The present work focuses on the incorporation of iron oxide, nickel oxide and chromium oxide in peraluminous borosilicate glasses from the SiO₂-B₂O₃-Al₂O₃-CaO-Na₂O-Li₂O-La₂O₃ system. They are studied in the context of future nuclear waste conditioning. The specificity of this type of glasses (peraluminous) is a lack of modifier elements (Na₂O, CaO) compared to the amount of alumina. This study was divided in two steps. First, the incorporation of iron oxide, nickel oxide and chromium oxide added separately to the glass was conducted, in order to understand their specific impact on the glass, in terms of incorporation limit, crystalline phases above this limit, glass structure around those elements and properties (viscosity, Tg). Second, the incorporation of the three oxides at once, to get closer to the real waste glass system and to detect possible synergies between these elements. Added one by one to peraluminous glasses, iron oxide and nickel oxide display high incorporation limits in peraluminous glasses at the micro-structural level (about 17.5 and 12 wt. % respectively after quenching). However, chromium oxide has a low solubility, about 0.5 wt. %. For the structural aspect, the proportions and coordination of Fe²⁺ and Fe³⁺ in the iron oxide doped glass was quantified through Mössbauer spectroscopy, showing a large contribution of Fe³⁺(6). UV-Visible spectroscopy also allowed the determination of the valence and coordination of nickel and chromium in their respective glasses, Ni²⁺(4) and Ni²⁺(5) on the one side, Cr⁶⁺(4) and Cr³⁺(6) on the other side. In terms of their impact on the properties of the glass, it appears that the addition of each of those oxides has little impact on the Tg of the glass. However, iron and nickel oxide have a strong impact on the viscosity of the glass melts, an increase in their amounts in the glass leading to a strong fludisation of the melt. The addition of chromium oxide, limited to a short range [0.0; 2.0] wt. %, has a negligible effect on the glass viscosity. When iron oxide, nickel oxide and chromium oxide are added together to peraluminous glasses, it appears that their behavior regarding crystallization is close to that of chromium oxide, with a low solubility limit mainly determined by the chromium oxide content. The crystalline phases appearing above this limit are also similar to those already identified in chromium doped glasses. In some glasses less rich in chromium oxide, a second crystalline phase is observed, spinel-like (Ni²⁺, Fe²⁺)(Cr³⁺, Fe³⁺, Al³⁺)₂O₄. When they are added together and in a more narrow range , the effect on viscosity of those oxides is only slight, without any noteworthy synergies. The long-term behavior of those glass was also studied (V₀, VR). It appears that their behavior during water alteration is very close, whether they are homogeneous glasses below the Fe, Ni, Cr solubility limit , or glasses presenting with crystallization above it
Debure, Mathieu. "Étude de la dissolution de verres borosilicatés en présence de minéraux magnésiens modèles représentatifs des minéraux de l'argilite du Callovo-Oxfordien." Electronic Thesis or Diss., Paris, ENMP, 2012. http://www.theses.fr/2012ENMP0047.
Borosilicate glasses dissolution has been studied in presence of magnesium minerals. Those minerals (dolomite, illite, smectite…) belong to the Callovo-Oxfordian (COx) claystone layer, studied in France as a potential site for nuclear waste disposal. Such minerals contain magnesium, an element able to sustain glass alteration when it is available in solution. In the confined media of the wastes disposal, thesolids reactivity controls the solution composition and can be the driving force of nuclear glass alteration. Experiments show that magnesium carbonates (hydromagnesite and dolomite) increase in the glass alteration: the precipitation of magnesium silicates consumes silicon which slows down the formation of the glass passivating layer. The lower the magnesium mineral solubility, the lower the glass alteration.The purified clay phases (illite, smectite…) from the COx layer increase the glass alteration. Half the magnesium was remplaced by sodium during the purification process. In such conditions, the effect of clay phases on glass alteration is in part due to the acidic pH-buffering effect of the clay fraction. The GRAAL model implemented in the geochemical transport code HYTEC has confirmed and quantified the mechanisms put in evidence in the experiments. Cells diffusion experiments where the two solids were separated by an inert diffusion barrier allow to valid reactive transport modelling. Such experiments are more representative of the glass package which will be separated from the COx by corrosion products. They show that glass alteration rate is reduced when solids are not close
Crémoux, Tatiana. "Physico-chimie aux interfaces de systèmes vitreux à charge d'espace." Thesis, Bordeaux 1, 2013. http://www.theses.fr/2013BOR14972/document.
The purpose of this work is to control physicochemical properties of glasses surfaces using a thermal polarization treatment. For this, the implementation of a space charge layer has been characterized for various silicates and borosilicates glasses. These comparative studies have shown that cations depletion from anode toward cathode induces both an electric field and structural local changes. To go further, we demonstrated that there is a plasma formation between anode and glass surfaces which could be the cause of ionic exchange phenomena leading to the formation of nitrogen NO2/N2O4 entities entrapped inside glass network. Subsequently, physicochemical properties studies of polarized surfaces were performed. Preliminary results concerning the space charge influence on (i) surface wettability, (ii) surface chemistry and (iii) optical responses of adsorbed molecules on poled glass surface have been obtained
Cailleteau, Céline. "Influence de la morphologie du gel sur la cinétique d'altération des verres borosilicatés : rôle du calcium et du zirconium." Phd thesis, Ecole Polytechnique X, 2008. http://pastel.archives-ouvertes.fr/pastel-00004828.
De, Bonfils Julien. "Effets d'irradiations sur la structure de verres borosilicatés - Comportement à long terme des matrices vitreuses de stockage des déchets nucléaires." Phd thesis, Université Claude Bernard - Lyon I, 2007. http://tel.archives-ouvertes.fr/tel-00177241.
Dans un premier temps, les mesures macroscopiques (dureté, gonflement) et à moyenne échelle (Raman, ATR-IR) ont montré que les matrices vitreuses, et en particulier la base borosilicate de sodium, subissent des modifications structurales qui se stabilisent à partir d'une dose 2,3.1013 at.cm-2 correspondant à une durée de stockage estimée à 300 ans dans le cas du verre R7T7.
Dans un deuxième temps, nous avons démontré expérimentalement et par simulation que les ions terres-rares sont regroupés dans deux grands types d'environnements à l'intérieur des verres : Le premier environnement clairement identifié comme silicaté, le second attribué à un site riche en bore.