Thèses (M.Sc.)--Université de Sherbrooke (Canada), 2000. / Titre de l'écran-titre (visionné le 20 juin 2006). Publié aussi en version papier.

Thèse de doctorat : Physique et Chimie de la Matière et des Matériaux : Nancy 1 : 2007. / Titre provenant de l'écran-titre. Bibliogr.

In recent years, the urgency of environmental and health protection regulations has significantly intensified the search for new, environmentally friendly anticorrosive coatings in heavy industry. While waterborne, high solids or powder coatings have emerged as alternatives, solvent-borne coat-ings still dominate the market, contributing to polluting and toxic volatile organic compound (VOC) emissions. UV-curable coatings offer a compelling solution with low environmental impact and efficient pro-duction processes that avoid VOC emissions, reduce energy consumption significantly, and lower product costs. Applying UV-curable coatings, which cross-link with UV radiation in a few seconds and without temperature application, is an innovative strategy that could meet the current envi-ronmental protection needs. This technology's superiority over traditional ones is evident in its higher production efficiency, avoidance of VOC emissions, lower energy spending production pro-cesses, and low investment in the production plant, all of which contribute to reducing product costs and preserving the environment. The technical-scientific aim of the proposed project is to develop a novel corrosion protective sys-tem cross-linked by UV radiation for the inner surface of piping. The system provides a new UV-curable coating formulation with outstanding performance and an effective technology for applica-tion and cross-linking inside a pipe's closed space. The proposed project directly responds to the urgent need for innovation in the pipes industry. The current production processes, which rely on catalytic ovens operating between 80 °C and 130 °C and using solvent-borne epoxy-based coatings, are highly polluting and energetically expensive, significantly inflating the product's cost. By revolutionizing these processes with a more sustainable and cost-effective solution, we can potentially reduce the overall cost of production, a key benefit that will interest industry stakeholders. Developing UV-curable coating technology for metal protection represents the new frontier of knowledge for the sustainability of corrosion protection treatments, respecting the environment, the workers’ health involved in the process, and the economy of the production processes.

No description available.

Les alliages d'aluminium utilisés dans le secteur aéronautique sont sensibles à la corrosion. Une protection de ces pièces peut être assurée grâce à l'élaboration de films anodiques colmatés, le colmatage avec un sel de Cr(VI) garantissant jusqu'à présent les meilleures propriétés de tenue à la corrosion. Toutefois, les composés à base de chrome Cr(VI), classés CMR, sont en passe d'être totalement interdits par la directive environnementale REACH, ce qui conduit les industriels à développer de nouveaux procédés alternatifs. Or, une revue bibliographique a mis en évidence que les procédés existants sont empiriques et qu'il existe des lacunes dans la compréhension des mécanismes de colmatage. L'objectif de cette thèse a donc consisté à identifier les facteurs conditionnant le colmatage, notamment la pénétration du solvant et des sels dans les pores, en relation avec les caractéristiques chimiques et microstructurales des films anodiques non colmatés. Les caractéristiques du film anodique non colmaté ont été tout d'abord amplement étudiées, notamment par des techniques innovantes. La tortuosité a ainsi été évaluée pour la première fois quantitativement, par MEB-FEG et BET, en fonction de la nature de l'alliage. Des mesures dynamiques de mouillabilité ont révélé par ailleurs qu'une tortuosité importante peut constituer une limitation pour la pénétration du solvant lors du colmatage. La caractérisation des charges de surface du film anodique non colmaté a indiqué en outre que les interactions avec les cations du bain de colmatage sont défavorables (répulsions) en milieu acide, sauf à un pH donné, pour lequel la charge globale s'annule. Après différents colmatages, les modifications des revêtements ont été étudiées en termes de composition chimique, de charges superficielles et de morphologie, ce qui a permis de proposer des mécanismes réactionnels. En particulier, pour le nouveau procédé de colmatage, il a été montré que ce n'est qu'à l'issue de la seconde étape de colmatage que le revêtement constitue une barrière à la pénétration d'un électrolyte agressif. Enfin, l'impact des différentes étapes de colmatage a été analysé au regard du comportement en corrosion, en fatigue et en fatigue-corrosion. / Aluminum alloys used in the aeronautic field are subject to corrosion. Sealed anodic films act as an efficient solution for the protection of aircraft parts, sealing using hexavalent chromium salts providing the best anticorrosion behavior so far. However, REACH environmental law leads to totally ban chromium (VI) based compounds which are CMR, thus forcing surface finishers to develop new alternative processes. A review has firstly shown that existing processes are mainly empirical and sealing mechanisms are far from being fully understood. So, this thesis aims at identifying sealing key factors that especially drive solvent and penetration into pores of the porous anodic film. Secondly, chemical and microstructural characteristics of unsealed anodic film have been widely studied, especially using innovative techniques. For instance, tortuosity was quantitatively evaluated for the first time, by FEG-SEM and BET analysis, as a function of the alloy nature, while wettability measurements have revealed that a high tortuosity limits water penetration during sealing. Surface charges characterization has also highlighted that working in acidic conditions has usually an adverse effect on interactions between film and cations, except for a special pH value for which global charge becomes zero. Thirdly chemical composition, superficial charges and morphology modifications of the coatings have been studied at each step of sealing, allowing to propose reactional mechanisms. In particular, it is only after the second step of the new sealing process, that the coating becomes an effective barrier against aggressive electrolyte. Finally, the impact of the different sealing treatments on corrosion, fatigue and fatigue-corrosion behaviors has been pointed out.

Ces travaux de thèse portent sur le développement d'un revêtement multifonctionnel issu de la voie sol-gel pour la protection anticorrosion et anti-usure de pièces de pompes. Le matériau d'étude est un acier laminé non allié DC04, très sensible à la corrosion et de topographie irrégulière. Il a été démontré la faisabilité du développement d'un revêtement hybride architecturé nanocomposite, densifié en extrême surface et élaboré par voie sol-gel sur l'acier DC04. L'architecture est basée sur un gradient de concentration de couches hybrides non chargées et chargées de nanoparticules de zircone. La bicouche primaire, qui est non chargée et d'une épaisseur de 5 microns, est adhérente, couvrante, nivelante et présente de très bonnes propriétés anticorrosion, jusqu'à 1000 heures lors de l'immersion dans l'eau de ville à 60°C. L'introduction de nanoparticules de zircone dans le sol hybride permet d'obtenir une couche supérieure plus épaisse de l'ordre d'une dizaine de microns dont la surface a été densifiée par traitement laser. Les systèmes architecturés ont été caractérisés par une méthode innovante qui combine les tests d'usure Taber, les observations microstructurales et la spectroscopie d'impédance électrochimique. Des analyses spectroscopiques par RMN des noyaux 13C, 29Si et 27Al ont mis en évidence l'importance de contrôler les réactions de polymérisation inorganique et organique pour l'obtention de revêtements performants en anticorrosion. La modification de la structure de la matrice hybride organique- inorganique permettant l'insertion d'une plus grande quantité de cérium sans détériorer les propriétés anticorrosion du revêtement. / This thesis focuses on the development of a multifunctional sol-gel coating for corrosion and wear protection of pump parts. The studied material is a DC04 laminated carbon steel, very sensitive to corrosion and with an uneven topography. Feasibility of the development of an architectured hybrid coating, densified on the extreme surface and prepared by the sol-gel route on the DC04 steel has been demonstrated. The architecture is based on a gradient of concentration of zirconia nanoparticles imbedded in an aluminosilicated hybrid matrix. The resulting bilayered primer in the range 5-6 microns is adherent, covering, leveling and presents high-performance anticorrosion properties, up to 1000 hours when immersed in tap water at 60 ° C. The introduction of zirconia nanoparticles in the hybrid sol allows to obtain a thicker upper layer, in the range 8-10 microns, which surface has been densified by laser treatment for few nm in deep. Architectured systems were assessed by an innovative method which combines Taber wear tests, microstructural observations and analysis by electrochemical impedance spectroscopy. 13C, 29Si and 27Al NMR spectroscopies have highlighted the importance of controlling both the organic and inorganic polymerisation reactions to obtain efficient anticorrosion coatings. Moreover, these results demonstrate that the modification of the organic-inorganic hybrid matrix structure allows the introduction of a higher amount of cerium, as corrosion inhibitor, without damage for the anticorrosive properties of the coating.

Thèse de doctorat : Physique : Nancy 1 : 2009. / Titre provenant de l'écran-titre.

No description available.

Estuda o desempenho de diferentes anticorrosivos, adicionados ao óleo de soja aditivado com o Irganox L 109, um antioxidante. O objetivo é verificar qual deles oferece melhor proteção ao latão e ao aço, simultaneamente. Ensaios de perda de massa e análise potenciodinâmica foram feitos com essa finalidade. Essas formulações foram caracterizadas com ensaios de viscosidade, curvas de resfriamento, espectroscopia de infravermelho e ângulo de contato. O estudo se estendeu, também, para o óleo de soja puro (sem adição de aditivos). Essas formulações de óleo de soja com diferentes concentrações de anticorrosivos e com uma concentração fixa de antioxidante foram submetidas a um processo de envelhecimento acelerado e após isso, foram novamente realizados os ensaios citados anteriormente. Com isso, pode-se comparar qual das formulações sofreu a menor variação na sua propriedade. Com isso, pode-se verificar que a formulação 0,1% 2-mercaptobenzotiazol foi a que apresentou o melhor comportamento para a finalidade requerida. / This work presents studies the performance of different anticorrosion additives, that were added in a composition of soybean oil and antioxidant Irganox L 109. The objective was determine which one offers good protection to the brass and steel, simultaneously. Tests of loss mass and potentiodynamic analysis were performed for this purpose. These formulations were characterized with tests of viscosity, cooling curves, infrared spectroscopy and contact angle measures. Similar studies were also extended to the pure soybean oil (without additives). The soybean oil formulations (different anticorrosion concentrations and fixed antioxidant concentration) were subjected to process of accelerated aging (oxidation) and new characterization tests were performed again. Comparative analyses between before and after oxidation tests were performed in order to verify which formulation had less variation on the properties. Results shown formulation 0.1% 2-Mercaptobenzothiazole has the best behavior for the purpose required.

Estuda o desempenho de diferentes anticorrosivos, adicionados ao óleo de soja aditivado com o Irganox L 109, um antioxidante. O objetivo é verificar qual deles oferece melhor proteção ao latão e ao aço, simultaneamente. Ensaios de perda de massa e análise potenciodinâmica foram feitos com essa finalidade. Essas formulações foram caracterizadas com ensaios de viscosidade, curvas de resfriamento, espectroscopia de infravermelho e ângulo de contato. O estudo se estendeu, também, para o óleo de soja puro (sem adição de aditivos). Essas formulações de óleo de soja com diferentes concentrações de anticorrosivos e com uma concentração fixa de antioxidante foram submetidas a um processo de envelhecimento acelerado e após isso, foram novamente realizados os ensaios citados anteriormente. Com isso, pode-se comparar qual das formulações sofreu a menor variação na sua propriedade. Com isso, pode-se verificar que a formulação 0,1% 2-mercaptobenzotiazol foi a que apresentou o melhor comportamento para a finalidade requerida. / This work presents studies the performance of different anticorrosion additives, that were added in a composition of soybean oil and antioxidant Irganox L 109. The objective was determine which one offers good protection to the brass and steel, simultaneously. Tests of loss mass and potentiodynamic analysis were performed for this purpose. These formulations were characterized with tests of viscosity, cooling curves, infrared spectroscopy and contact angle measures. Similar studies were also extended to the pure soybean oil (without additives). The soybean oil formulations (different anticorrosion concentrations and fixed antioxidant concentration) were subjected to process of accelerated aging (oxidation) and new characterization tests were performed again. Comparative analyses between before and after oxidation tests were performed in order to verify which formulation had less variation on the properties. Results shown formulation 0.1% 2-Mercaptobenzothiazole has the best behavior for the purpose required.