Дисертації з теми "Revêtements protecteurs – Propriétés thermiques"
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Irigoyen, Maylis. "Durabilité des revêtements organiques anticorrosion : caractérisation de la dégradation." Toulon, 2002. http://www.theses.fr/2002TOUL0013.
Faugeroux, Olivier. "Caractérisation thermophysique de revêtements de protection thermomécanique par méthode photothermique impulsionnelle." Perpignan, 2001. http://www.theses.fr/2001PERP0459.
Guinard, Caroline. "Influence des propriétés morphologiques et mécaniques des barrières thermiques sur la fissuration interfaciale induite par perçage laser impulsionnel." Thesis, Paris Sciences et Lettres (ComUE), 2016. http://www.theses.fr/2016PSLEM068/document.
Many aircraft engines parts such as combustion chambers are drilled with numerous cooling holes. These holes, generally performed by a high power laser machine can induce damages in the part materials. On thermal barrier coatings systems, cracking can lead to spalling of the coating occurs at the ceramic / bond-coat layer interface during laser drilling. This thesis presents elements of understanding of the interfacial crack formation end propagation phenomena. In this purpose, a specific protocol was used, consisting of interrupted drilling process. Moreover, in order to understand the influence of the bond coat and the ceramic / bond coat interface on cracking, a wide range of samples with specific morphological and mechanical properties were selected. With this in mind, the bond coat was modified by varying spraying parameters, spraying process and also by post treatments on the bond coat. The link between these interfaces and the associated damages due to laser drilling are presented through 2D and 3D observations, destructive and non-destructive, as well as the study of residual stress modification before and after laser drilling for several thermal barrier coatings systems. For further reducing the interfacial crack, several drilling strategies are considered through the laser peak power variation between the different laser pulses needed to drill through the multi-layer material. The results offer interesting perspectives for improving crack resistance of aeronautical engines parts
Boissonnet, Germain. "Factors influencing the thermal insulation potential of different thermal barrier coating systems." Thesis, La Rochelle, 2019. http://www.theses.fr/2019LAROS007.
In aeronautical gas turbine engines, the metallic materials employed in the hottest sections are subject to very harsh chemical environments at high pressures and temperatures. Therefore, thermal barrier coating systems (TBCs) are applied onto nickel-based superalloy substrates. These multi-layered systems (ceramic yttria-stabilized zirconia (YSZ) / MCrAl or NiPtAl bond coats / cooled substrate) lower the temperature at the components surface, which ensures an adequate thermomechanical behaviour and reduces the oxidation/corrosion rates. However, the increase of the turbine inlet temperature (increased engine performance) brings about new degradation phenomena (e.g. CMAS) and loss of efficiency of the current TBCs. Therefore, understanding the evolution of the insulation ability of TBCs in such harsh environments is key from both the scientific and technological perspectives to estimate the lifetime of these coatings, hence that of the engines. Based on current plasma-sprayed (PS) and electron-beam physical vapour deposited (EB-PVD) YSZ coatings, this thesis seeks to provide a better comprehension on the relationships between the intrinsic properties of the current TBCs and their thermal insulation capacity as a basis for the development of future coatings. Also, this work studies an alternative solution to create a TBC made of hollow alumina microspheres by the slurry route. We will show that the sintering of the YSZ, the evolution of crystal phases, the reactions between YSZ and CMAS and the growth of thermal oxides alter the thermal diffusivity to different extents. In contrast, the evolution of the thermal diffusivity with temperature is less marked with the slurry alumina coatings, which appear more stable when hybrid Ar/air annealing atmospheres are employed upon their synthesis
Thibault, Marc. "Élaboration et caractérisation de revêtements formés par hydrolyse et condensation d'alcoxysilanes sur tôles magnétiques à grains orientés et non orientés." Lille 1, 1995. http://www.theses.fr/1995LIL10110.
Ravaux, Alice. "Réalisation et étude de dépôts composites multi-échelle élaborés par projection plasma pour applications tribologiques à hautes températures." Thesis, Limoges, 2014. http://www.theses.fr/2014LIMO0077/document.
Nowadays, tribology has a high energetic impact on economic and industrial areas. Thus, reducing wear and friction of mechanical parts has become a real stakes for various industries. This study is focused on the wear prevention of mechanical parts subjected to severe operating conditions like high temperatures.The realization of protective ceramic-metal coatings is thus particularly appropriated to improve corrosion resistance induced by the high temperatures, with a suitable alloy, and the wear resistance, thanks to the ceramics hardness. Furthermore, researches development in the nanoscale field have shown the interest of scale reduction on the improvement of coatings tribological properties. Thermal spraying is then the most appropriate process for the realization of such coatings.In this work, multi-components (ceramic-metal) and multi-scales (micrometric-nanometric) coatings are developed by plasma spraying in order to give an answer to the high temperature tribological resistance issue. Coatings are realized using a three-cathodes plasma gun (TriplexPro-200) which provides a more stable plasma jet and offers wide possibilities by an extended operating window. First, the special features of this kind of plasma gun will be studied in order to adjust the process to the complex realization of multi-scale coatings. An innovative approach using a hybrid spraying process was thus developed, combining conventional micrometric powder spraying and suspension of nanoscale powders spraying. In a second time, the steps leading to the production of such coatings will be detailed, and finally, their main properties and their tribological behavior will be studied
Saïdi, Salima. "Synthèse et formulation de résines fluorées : étude des propriétés antigraffiti." Nice, 2002. http://www.theses.fr/2002NICE5750.
Boudot, Aline. "Propriétés des revêtements de protection haute température pour pales de turbine haute pression." Toulouse, INPT, 1999. http://www.theses.fr/1999INPT034G.
The aim of this work was the characterization of the vacuum plasma sprayed or electrodeposited NiCoCrA1YTa coating, used for protection of H. P. Turbine blade. First, both massive coatings were characterized in terms of physico-chemical and mechanical properties. The electrodeposited alloy shows a less homogenous distribution of β and γ phases and, in this coating, yttrium is segregated in the material as oxides and precipitates. These distinctive features induce mechanical spallation of the oxide scales and lower mechanical properties for the electrodeposited coating. Then, influence of protective coatings on nickel-base single crystal superalloy was characterized. Few differences were observed between the vacuum plasma sprayed coating and the electrodeposited one. The coating effect is mainly dependant on its ductile or brittle behaviour. If the mechanical solicitations of the substrate/coating system are applied in the brittle field of the coating, this one presents a detrimental effect. In the other case, a positiv effect of the coating is observed which comes from the protection of substrate against environmental degradation
Gomart, Hector. "Modélisation des propriétés thermo-radiatives de revêtements à haute efficacité énergétique." Orléans, 2008. http://www.theses.fr/2008ORLE2050.
Veys, Delphine. "Évolution des propriétés physico-chimiques de surface des matériaux quasicristallins lors de sollicitations électrochimiques." Vandoeuvre-les-Nancy, INPL, 2004. http://www.theses.fr/2004INPL076N.
The main goal of this study is to understand how the surface properties of quasicrystalline and approximant alloys are modified when submitted to various kinds of electrochemical stress. The alloys are Al-based complex intermetallic phases of the AI-(Cu)-Fe-Cr system, submitted to either corrosion test in aggressive media or simply to oxidation and ageing in ambient conditions. Ln a first part, bulk alloys of the AI-(Cu)-Fe-Cr system were synthesized and their atomic structure was characterised. Then, the corrosion behaviour of these alloys was investigated with a view to identify the role of the chemical composition and of the crystallographic structure on their ability to resist corrosion attack in a medium containing citric acid and chloride anions. This work bas allowed us to âetermine the corrosion mechanisms and to identify some alloy compositions which demonstrate high-resistance against corrosion. The last part focusses on the evolution of surface structure and chemistry as a function of electrochemical stress. The topography, composition and structure of corroded samples were analysed. Ln addition, for AICrFe samples, we have highlighted an ageing phenomenon of the surfaces in ambient conditions. We have proposed a model describing the surface of these materials as a stacking of several layers with different chemistry. The surface ageing is modelled and related to the observed modifications of the chemical reactivity
Bouzziri, Miloudi. "Adhérence et propriétés physico-chimiques des couches de phosphate sur aciers et aciers revêtus de zinc." Lyon 1, 1994. http://www.theses.fr/1994LYO10201.
Hatte, Quentin. "Influence des conditions de mise en œuvre sur les propriétés de revêtements protecteurs : application à la corrosion sur acier." Thesis, Nantes, 2019. http://www.theses.fr/2019NANT4027.
Paints are conventionally used in the field of marine renewable energies to protect steel structures from corrosion. To improve the adhesion and therefore the durability of these coatings, surface treatments can be used. Usually, this is done by sandblasting. In this study innovative surface treatments were tested. The sol-gel and PVD technologies have shown good adhesion and durability properties in humid environments, making them attractive candidates for replacing the sandblasting step which mechanically weakens the paint system. In addition, an industrialization of these methods requires a perfect control of the processes. This is why the influence of the monitoring conditions on the sol-gel and PVD processes was studied. The sol-gel transition kinetics is affected by temperature and relative humidity which modify the properties of the gel formed. T and RH must therefore be measured to adjust the drying time. The growth of the PVD coating results in the formation of residual stresses that can be evaluated by a method detailed in this report. The study of these phenomena made it possible to make suggestions in view of improving the effectiveness of the coating. For example, the level and the sign of stresses can be modified by adjusting the thickness and bias voltage. Finally, many physicochemical characterization tests were used and the results obtained could be compared, that made it possible to evaluate the relevance of the various tests
Decarlis, Arnaud. "Modélisation de la conductivité thermique de matériaux hétérogènes : application aux revêtements de coque utilisés en acoustique." Aix-Marseille 1, 1998. http://www.theses.fr/1998AIX11076.
Cadoret, Yannick. "Effet du platine et du soufre sur l' oxydation des revêtements protecteurs β (beta)-NiA1 à haute température : applications aux barrières thermiques". Paris 6, 2005. http://www.theses.fr/2005PA066189.
Duquesne, Sophie. "Etude des procédés d'ignifugation de substrats polymères par revêtements intumescents : application aux polyuréthanes." Lille 1, 2001. https://pepite-depot.univ-lille.fr/LIBRE/Th_Num/2001/50376-2001-Duquesne.pdf.
Concernant le système PU/EG, une faible modification du processus de carbonisation naturelle du PU est observée. La caractérisation du processus de carbonisation, menée selon une approche physique met en évidence une aptitude à la déformation de la structure carbonée formée par dégradation du revêtement PU/APP. Aucours d'un incendie, cette structure va donc se déformer plutôt que de se fissurer et ainsi permettre un maintien des performances RF. Dans le cas du système PU/EG, l'épaisseur importante, la faible densité et, comme il est possible de le supposer la faible conductivité thermique du bouclier intumescent permettent de comprendre le mode d'action de l'EG
Antou, Guy. "Améliorations de revêtements barrières thermiques par un procédé de refusion laser in situ utilisant un laser à diodes." Strasbourg 1, 2004. https://publication-theses.unistra.fr/public/theses_doctorat/2004/ANTOU_Guy_2004.zip.
Yttria partially stabilized zirconia thermal barrier coatings (TBCs) are nowadays widely used to protect components of aero gas turbines against degradation at high temperature, corrosion and oxidation. However, these coatings degrade in service conditions. Therefore, to manufacture TBC which present both low thermal conductivity and high life-time is a real challenge. Engineering the coating architecture by an adapted process is a prerequise to modify TBC characteristics. In this study, laser remelting was combined to thermal spraying in order to modify the TBC properties. The purpose was to adapt TBC characteristics during their manufacturing process, without adding one or even more additional steps. In situ laser treatment (i) changes structure from lamellar to dendritic columnar; (ii) generates a pore architecture less sensitive to sintering, inducing then a best conservation of the thermal and mechanical properties during thermal treatments at high temperatures; (iii) improves the thermal insulation properties of the TBC by decreasing its thermal conductivity of about 30 %; (iv) decreases its permeability in order to diminish oxidation and corrosion phenomena; (v) increases the resistance to isothermal shocks (with the possibility to double the number of cycles); (vi) conducts to a metastable tetragonal phase more stable during thermal shocks; (vii) without modifying elastic response of the deposit
Barakat, Yosry Fathallah Moustafa. "Dopage du dioxyde de titane par oxydation anodique : étude analytique et structurale, conséquences sur les propriétés protectrices." Compiègne, 1987. http://www.theses.fr/1987COMP0E69.
Tlili, Brahim. "Caractérisation de films durs multicouches élaborés par pulvérisation magnétron : influence des conditions d'élaboration sur leurs propriétés." Phd thesis, Paris, ENSAM, 2010. http://pastel.archives-ouvertes.fr/pastel-00573968.
Maurin, Vanessa. "Revêtements poudres UV : mécanismes de polymérisation et étude des relations structures / propriétés." Thesis, Mulhouse, 2012. http://www.theses.fr/2012MULH4091.
In the frame of a project of the Agency National Research (France), the thesis deals with the study and the development of UV powder coatings dedicated to wood based panels. The work describes the main features of these formulations and the associated technology in order to offer a strong bibliography specific to this area. The experiments are based on model formulations containing an UV powder resin (diacrylate urethane or dimethacrylate polyester) and a photoinitiator. A mechanistic study allows highlighting the influence of temperature and viscosity, light intensity and atmosphere on the reactivity of the model formulations. It is also shown that the termination mechanisms specific to theses systems follow mixed processes: bimolecular, pseudo-monomolecular and primary radical termination. The predominance of the different processes is related to the reaction conversion. The building of the crosslinking network is then studied depending of the irradiation source: semi-industrial conveyor equipped with UV lamps or LED system emitting around 395 nm. The characteristics of the crosslinking network (Tg, crosslinking density, Young’s modulus) are linked to the final coatings properties (flexibility, scratch and solvent resistance). The incorporation of multifunctional acrylates affects the chains length and crosslinking density. To reach specific applications, it is finally proposed to add a silver-modified clay into model formulations to obtain homogeneous antibacterial UV powder coatings exhibiting good resistance properties
Lewis, François. "Étude sur les propriétés d'adhérence des revêtements fluorocarbonés déposés par plasma sur l'acier inoxydable 316L pour les stents coronariens." Thesis, Université Laval, 2010. http://www.theses.ulaval.ca/2010/26602/26602.pdf.
Coronary stents are medical devices used to provide internal scaffolding to stenosed arteries. This disease is characterized by the deposition of lipids on the artery wall, a decrease of the artery diameter and blood flow disturbance. The stents are mainly made of a metal structure coated with a polymer film. Despite their commercial success, many adhesion problems are reported after their expansion, such as coating delamination and cracking. These coating failures decrease the stent’s efficiency and durability. The aim of this thesis was to study this problem using fluorocarbon coatings deposited by plasma polymerization This thesis proposes a new technique, named Small Punch Test, to evaluate the coating adhesion. This method simulates the stent expansion on flat substrates, which facilitates the evaluation of the coating properties after deformation. Scanning electron microscope and atomic force microscope investigations showed the importance of the coating thickness on their cohesion properties. Cracks were observed on specimens with a coating thickness higher than 35 nm. To deposit coatings with a low density of nano-defects and to increase their stability in aqueous media, this research investigates the growth and properties of fluorocarbon films deposited on plasma etched substrates. Hydrogen plasma played a key role, with the formation of hydroxide as film growth initiator. During the first polymerization steps, hydroxides may lead to the formation of fluorocarbon coatings with low nano-defect density, high content in CF2 and long polymer chains, as observed by XPS, ToF-SIMS and FTIR. However, plasma etchings modified and lowered the oxide layer thickness of stainless steel and increased the sensitivity of samples to post-oxidation.
Masson, Cécile. "Caractérisation des films passifs formés sur aciers inoxydables en milieux électrolytiques : modélisation par spectrométrie d'impédance." Lyon 1, 1995. http://www.theses.fr/1995LYO10155.
El, Alaoui Sidi Mohammed. "Elaboration et étude des revêtements réfractaires sur un acier inoxydable austenitique Fe-Ni-Cr." Toulouse 3, 2005. http://www.theses.fr/2005TOU30095.
The rise in temperature of operation of the heat engines and in particular of the engines (combustion chambers, aeronautical turbines of engines. . . ) makes it possible to increase their output for energy saving. The major problem of operation at high temperature is that of the behaviour to oxidation of metals and alloys. The use of thermal refractory material barrier and diffusion barriers made up makes it possible to mitigate this problem. The effectiveness of these barriers depends on their formulation which is related to their conditions of manufacture. This work falls under the development of ceramic coatings (alumina) worked out by soft chemicals to protect the refractory stainless steels and super alloys against oxidation at very high temperature. These coatings are obtained by chemical way, on a substrate functionalized beforehand by a treatment of conversion. The results presented relate to an alumina coating on austenitic stainless steel substrate. A first stage consisted in optimizing the treatment of conversion and in particular the formulation of the bath to functionalize the substrate. The layers of conversion obtained are nanostructurées and present a character fractal. In a second stage, the use of the Experimental design methodology (M. R. E), us made it possible to optimize the properties of the alumina deposit; it is about a deposit induced by electrolysis and particularly member. Two significant parameters were studied: the time and density of current. These deposits characterized by spectroscopie of mass of the secondary ions (SIMS) and Diffraction of the X-ray reveal gradients of concentration in radiant what explains good resistance to chipping. The tests thermogravimetric showed a very significant improvement of the behaviour to oxidation at high temperature of steel
Ganda, Hassane. "Méthode de mesure de l'émissivité spectrale directionnelle de matériaux à haute température : mise au point et application à des revêtements céramiques." Toulouse 3, 1993. http://www.theses.fr/1993TOU30178.
Malassenet, Lise. "De l’étude des paramètres physico-mécaniques des revêtements vers le développement de finitions performantes sur bois en extérieur." Thesis, Université de Lorraine, 2015. http://www.theses.fr/2015LORR0204.
Wood used outdoors is subject to aesthetic damages and to dimensional variations due to alternation of dry and wet periods. Therefore, a protection with a coating is recommended. Coatings need to be soft enough to follow variations of wood and at the same time hard enough to be able to withstand possible damages (impact). Hence, mechanical properties of coatings play a major role in their service life. However in Europe, coating performances are mainly assessed through weathering tests followed by visual assessments, color and gloss measurements and adherence tests. The aim of this work is to develop a thorough methodology to assess coating performances in order to better understand the resistance of coatings to weathering. The final objective of this project is an industrial development of innovating wood coatings for outdoors with good performances to weathering during their service life. Through our study, performances of commercial coating were assessed using conventional standardized tests from the EN 927 series but also with other methods in order to gain an extensive understanding of their physic-mechanical properties. Hence, damping and indentation tests on coated wood were investigated as well as tensile tests on free films. Persoz pendulum was particularly used as a tool to approach easily and quickly mechanical properties of coatings. This work established a link between damping test results and coating performances exposed to artificial and natural weathering. Tensile tests on free films have supported these results as a good correlation between damping hardness and some mechanical properties was found. Last but not least, the analysis of damping hardness variations versus weathering time has lead to a better understanding in the development of damages and to the establishment of performance specifications. These results allowed us to select and formulate new UV-curing formulations for outdoors. They are made of a mixture of monomers and oligomers combined with photoinitiators. At this stage, the methodology developed to assess performances has allowed the selection of the best constituents to ensure good performances to weathering
Arfan, Éléonore. "Tenue thermomécanique des dalles d'impact des poches à acier en céramiques réfractaires." Cachan, Ecole normale supérieure, 2009. http://tel.archives-ouvertes.fr/tel-00661179.
The impact pad is a reinforced zone of the refractory lining of the bottom part of the steel ladle designed to resist against thermo-mechanical loads due to the liquid steel impact during filling. Results of an inquiry performed on a steel plant are first presented. Degradations observed on different kinds of impact pad materials have been indentified and the influence of process parameters on their life span has been evaluated. Mechanical experiments (compression tests and three-point bend tests) have been performed up to 1500°C on different alumina-magnesia refractories. They allow for the characterization of the thermomechanical behaviour and the strains due to phase-transformations at high temperatures. A thermo-elasto-viscoplastic model taking into account the phasetransformations is proposed. The last part deals with numerical simulations carried out with ABAQUS and FLUENT softwares. These computations aim at describing the thermal and mechanical behaviour of the impact pad during the steel making process, and more precisely during the impact of the liquid steel. Combined with micro-structural observations and refining process data, these simulations enabled us to figure out how the different types of loads might be responsible for the degradations observed on worn impact pads
Daniel, Priscillia. "Etude des propriétés électriques de câbles isolés au polyéthylène réticulé en présence de cavités gazeuses et vieillis sous tensions DC ou DC avec harmoniques." Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAT114.
In order to accommodate large scale renewable energy, electrical networks integrates more and more high-voltage direct current (HVDC) systems. Interface between AC and DC networks is ensured by power converters which also generate harmonics. It is known that during crosslinking process of polyethylene (XLPE), microcavities appear inside polymer matrix. This study aims to examine possible impact of these harmonics in presence of microcavities. Depending on their size and on the electrical field, partial discharges (PD) can occur in these microcavities. Two types of cables have been aged: a medium voltage AC (MVAC) cable with millimetric cavities induced artificially and a model cable with an HVDC XLPE grade. MVAC cable sections have been submitted to DC voltage under temperatures between 90 to 120°C. Model cables have been subjected to superimposed DC plus 1800 Hz AC voltages under temperatures from 70 to 90°C. Ageing have been characterized by PD, current and dielectric spectroscopy measurements. In presence of millimetric cavities, ageing have caused a decrease in PD inception voltage (PDIV) and an increase in PD magnitude. For model cable, PDIV values have been assigned, according to a proposed model, to cavities of about 10 µm in diameter. Conduction currents were increased and space charges threshold field decreased depending on ageing. Finally, dielectric spectroscopy characterisations have shown differences between thermal and electrothermal ageing. Electrical field enhancement factors under DC voltage have been estimated in various cavity geometries thanks to numerical simulations. These factors reveal to be higher than the ones used under AC voltage. Space charges involvement in PD phenomena inside cavities is discussed based on measurements and simulations
Boulesteix, Claire. "Synthesis, environmental degradation and repairability of slurry aluminium coatings elaborated on steels employed in power plants." Thesis, La Rochelle, 2017. http://www.theses.fr/2017LAROS022/document.
Higher energy efficiencies can be achieved by the increase of temperatures and pressures in power plant, thus allowing the reduction of the polluting emissions. Therefore, more efficient materials, compared to those currently employed, have to be used in order to resist to harsh environmental conditions (high temperatures, steam, pressure…). Despite of the good mechanical properties of many steels, the elaboration of a protective coating able to form a dense, protective and stable oxide layer at high temperature, is necessary. Thus, in the framework of the “POEMA” European project, the mechanisms of the formation of aluminium diffusion coatings were studied on ferritic-martensitic and austenitic stainless steels that are currently employed in power plants. The sealing of cracks eventually created during the aluminisation of steels was also studied. The degradation mechanisms of the B2-(Fe (Ni))Al coatings were then studied in steam and in air at 650 and 700°C up to 10000 hours and under different pressures (1 and 300 bar). We have demonstrated that the pre-oxidation induced during the elaboration of coatings grew a thin protective oxide scale composed of α-Al2O3 which developed further upon oxidation. Nevertheless, the long exposures under high steam pressures promoted the cationic diffusion of Fe, thus allowing the formation of small surface oxide nodules. Finally, the dissolution mechanisms of coatings with a diluted acid have been studied in order to demonstrate the possibility of strip and realuminise the materials initially coated
Houel, Amélie. "Revêtements polyesters hybrides organiques-inorganiques par voie sol-gel." Phd thesis, INSA de Lyon, 2011. http://tel.archives-ouvertes.fr/tel-00821407.
Skiba, Stephane. "Caractérisation thermomécanique et détermination de lois de comportement de revêtements abradables de compresseurs basse et haute pression de turboréacteurs pour de larges gammes de vitesses de déformation et de températures." Thesis, Université de Lorraine, 2019. http://www.theses.fr/2019LORR0324.
Abradables coatings used to minimize inter-stage leakages in aircraft engines, take part in severe interaction with blades. Concerning the compressor stages, those interactions take place in environments where temperatures go up to 350°C and 800°C respectively for low-pressure and high-pressure compressors (LPC and HPC). High-speed rotation of blades leads to complex dynamic solicitation within abradable material combining compression, tension, and shear components. The thermomechanical behavior knowledge of those materials under extreme solicitations is a key point in the understanding of blades-abradables interaction and their numerical simulation. This work aims to characterize the thermomechanical behavior under representative conditions of two abradable materials, an AlSi-PE from the LPC and a CoNiCrAlY-hBN from the HPC. The experimental bench of the Split Hopkinson Pressure Bar allowed investigation in compression for strain-rates up to 103 s-1 and for temperatures up to 350°C and 800°C depending on the abradable material. Quasi-static tests in temperature completed this characterization of the compression response. In addition, dynamic shear tests and quasi-static and dynamic Brazilian tests were performed on the AlSi-PE abradable. This thermomechanical behavior characterization was able thanks to specimens extracted from thick abradable coatings. The AlSi-PE abradable was able to highly deform under compression loading. A sensibility to the strain-rate and the temperature was identified. The CoNiCrAlY-hBN abradable showed a fragile behavior with no sensibility to the temperature but a sensibility to strain-rate. The thermomechanical behavior in compression of both abradable, from 10-3 s-1 to 103 s-1 and temperatures were modeled with bilinears behavior laws. In addition, a plastic model based on the Johnson-Cook law is introduced for the AlSi-PE abradable
Préauchat, Boris. "Élaboration et caractérisation de barrières thermiques à base de zircone obtenues par dépôt chimique en phase vapeur assisté par un plasma micro-ondes : mise au point du procédé, propriétés physiques et stabilité des revêtements vis-à-vis du vieillissement thermique." Vandoeuvre-les-Nancy, INPL, 2001. http://docnum.univ-lorraine.fr/public/INPL_T_2001_PREAUCHAT_B.pdf.
A reactor for manufacturing zirconia-based thermal barrier coatings by microwave plasma enhanced chemical vapour deposition has been optimised. Deposition rates higher than 250 μm/h have been achieved (on 20 mm diameter plane substrates). A new evaporation and gas injection deviee has been designed to obtain coatings exhibiting uniform thickness and yttria content. Plasma activity has been homogenised. A new sample-holder has been designed to investigate coating morphologies at deposition temperature between 500°C and 900°C. Once optimum deposition parameters were defined, three morphologies of yttria partially stabilised zirconia coatings were studied by scanning electron microscopy and X-ray diffraction. A dendritic growth of columns of the tetragonal nontransformable t' phase along the [100] direction at high deposition temperature was observed. The coatings deposited at 700°C and 900°C exhibited satisfactory stability towards isothermal heat treatments at 1100°c to 1400°C. Using X-ray diffraction analysis, a destabilisation scheme of the metastable " t' " phase has been proposed. Investigations of the coating porosity, roughness, thermal conductivity and resistance towards thermal cycling supplemented this microstructural and crystallographic study. These properties would allow the use of these yttria-zirconia coatings in typical thermal barrier applications
Gonzalez, Hernandez Andrés Giovanni. "Etude du comportement à haute température de revêtements nanostructurés élaborés par projection thermique (combustion et plasma) à partir de poudres et de suspensions." Thesis, Limoges, 2014. http://www.theses.fr/2014LIMO0046/document.
The research topic of this thesis is devoted on the study of the behavior of nanostructured coatings based on zirconia, which extends from the characterization of raw materials through manufacturing, characterization of the properties of the coatings and then end up in the study of their behavior at high temperature, especially in strong environments to make them comparable. Three kinds of techniques were used for manufacturing the coatings: flame spraying (FS), atmospheric plasma spraying (APS) and suspensions plasma spraying (SPS).Three types of substrates were used and characterized for manufacturing the coatings: a low carbon steel (AISI/SAE12L15), stainless steel 304L and superalloy Inconel 718. A surface treatment of blasting with corundum was applied to all substrates in order to generate a noticeable roughness (> 5 µm), then apply a bond coat of Ni-Al-Mo for the technique FS and a bond coat of NiCrAlCo-Y2O3 for the technique APS and SPS. The coatings were characterized to know and correlate the morphology of the cross section and surface, elemental composition of the zones of interest, phases, thickness, porosity, microhardness, vibrational groups, corrosion resistance and wear resistance. Additionally, the most important was to characterize the high temperature performance of the coating by tests as thermal shock, isothermal oxidation and hot corrosion with salts. For knowing the behavior of the coatings after being subjected to these tests, a study of the morphology of the surface and cross-section, elemental composition and phases analysis in the regions of interest have also been carried out
Scaringella-Guerritat, Yohann. "Contribution à l'optimisation des propriétés des revêtements utilisés pour la protection des moules en fonderie d'aluminium : Mise en évidence des caractéristiques influant sur la durée de vie et étude de procédés alternatifs pour l'application." Thesis, Limoges, 2015. http://www.theses.fr/2015LIMO0095.
Montupet is specialized in the manufacture of aluminium foundry components for the automotive industry. The metallic molds used for aluminium cylinder heads are protected by a specific coating called die coating. The main objective of this die coating is to protect the steel tool from chemical corrosion of the liquid alloy. Because of its thermal properties, another of its aims is the adjustment of the thermal exchanges between the mold and the solidifying aluminium, which strongly affects the final microstructure of the alloy. The process used nowadays to coat the die coating on the steel mold walls consists in spraying manually a suspension. However, this process does not allow to obtain reproducible characteristics of the coated layers necessary to control the local solidification gradients. Furthermore, the current tools suffer from the inadequate protection of the die coating, which leads to premature wear resulting in important costs and a decrease of the efficiency of the industrial tool. In the frame of the PROOF project, aiming in the automatisation of the die coating projection, several objectives were set: better know what should be the physico-chemical properties of the die coating and realize a technological jump by creating a long-life or even permanent coating. Firstly, this work shows a complete characterization of the physico-chemical state of the suspensions used nowadays as well as the study of their behavior during spraying. Then, once the coatings were produced by Air Plasma Spraying (APS), it appeared necessary to compare their thermal properties to the ones measured on the die coatings. Hence, thermal diffusivity values have been measured. Afterwards thermal conductivity of the studied coatings have been calculated and finally experimentally checked. Eventually, this work shows the tools developed within the company in order to test the plasma coatings and to check their thermal and chemical compatibility to the process of aluminium casting. These trials in real or semi-real conditions allow the efficiency comparison of the whole studied coatings
Marc, Teodor paul. "Conception et réalisation de structures routières à hautes performances." Thesis, Artois, 2011. http://www.theses.fr/2011ARTO0214/document.
The doctoral thesis analyses certain factors of influence that, through large temperature variations, frequently have a negative impact upon road pavements, especially the bituminous layers, with a view to determine the thermal-physical properties (thermal conductivity, specific heat, diffusive thermal, thermal effusion and emissivity) and to design and realize asphalt layers with better thermo-physical, and physical and mechanical characteristics.Practically, the studies highlighted in the thesis focus mostly on determining the thermal characteristics of asphalt mixtures, characteristics which help to combat the influence factors resulting from environmental conditions to which road structures are subject continuously road in the construction and repair stages, as well as during their service life. Due to being aware of temperature distribution in each bituminous layer of the road structure, the stresses occurring from variations of temperature can be controlled. The daily and seasonal fluctuations of air temperature, the intensity of solar radiation, the materials that make up the road structure layers by their geometry and surface conditions are some of the most important factors that significantly endanger the stability of the road structure.Positive contributions have been made on improving the thermal characteristics through designing and realizing asphalt mixtures in the composition of which, in addition to basic materials, flying ash was used as partial or total replacement for filler. This helps to obtain higher thermo-physical properties that have a favorable effect on physical and mechanical characteristics.Based on experimental results, some interesting and in the same time extremely valuable conclusions have been formulated opening a range of opportunities for further research in the field of road infrastructures
Termoss, Hussein. "Préparation de revêtements de nitrure de bore (BN) par voie polymère précéramique : étude des paramètres d’élaboration : caractérisations physico-chimiques." Thesis, Lyon 1, 2009. http://www.theses.fr/2009LYO10145/document.
The aim of this work was to prepare boron nitride coatings onto different substrates using the Polymers Derived Ceramics (PDCs) approach. In that way, BN coatings were obtained onto graphite, pure silica and metal especially titanium. The first part of this thesis was to study parameters (of the solution used and of the dip-coating process), to obtain the best coatings in terms of morphology, cristallinity and chemical composition. The second part was dedicated to BN coatings obtained onto metal substrates using an alternative thermal treatment allowing the polymer-to-ceramic conversion without any damage for the metal. Actually, annealing by infrared irradiation allows heating only the coating, energy being reflected by the metal
Perrudin, François. "Étude de la dissolution de diverses terres rares dans des liquides silicatés (CMAS) de composition variable : contribution au développement des barrières thermiques en ZRO₂-RE₂O₃ (RE=La-Lu)." Thesis, Université de Lorraine, 2018. http://www.theses.fr/2018LORR0277/document.
Fine particles of sand, dust or volcanic ashes ingested by aircraft engines are well-known to damage Thermal Barrier Coatings (TBC) when they infiltrate their porous microstructure as molten silicate (CMAS). They are mainly constituted of CaO-MgO-Al2O3-SiO2 in variable proportions and also contain metallic oxides. RE2Zr2O7 compositions are TBC candidate materials as they have shown efficiency to mitigate CMAS infiltration due to their reactivity with synthetic CMAS. Indeed, the dissolution reaction leads to rapid sealing of the topcoat porosity mainly due to the formation of crystalline Ca2Gd8(SiO4)6O2 apatite. However, many rare-earth silicates are likely to compete with apatite crystallization and little is known on reaction kinetics and thermodynamics involving RE2O3 and multi-component CMAS system. This work aims to determine the influence of CMAS and rare earth composition on dissolution and precipitation mechanisms. A simplified CAS was first selected with eutectic (1170°C), 65SiO2-26CaO-9Al2O3 (mol. %) composition. Dissolution of various RE2O3 with increasing basicity (RE = Yb, Dy, Gd, Sm and Nd) as well as synthetic apatite and cyclosilicate Ca3RE2(Si3O9)2 phases was then performed at 1200°C in CAS-melt. Finally, fixed MgO and Fe2O3 contents were added to CAS melt with an increasing CaO/SiO2 ratio. The results showed that RE2O3 dissolution mechanism is indirect. Apatite formation results from local equilibrium at the interface with solid RE2O3 whatever the rare earth and CMAS composition. Its crystallization is favored when Ca2+ and RE3+ ionic radii are close as they are both distributed within 9-fold coordination sites. Conversely, Ca and RE mismatch leads to rapid nucleation of cyclosilicate phase in CAS as they are preferentially distributed within a 6-fold coordination site. MgO and Fe2O3 addition in CAS as well as RE2O3 basicity tend to increase RE solubility in silicate melt. Phases in thermodynamic equilibrium strongly depend on CMAS composition but generally exhibits lower RE solubility and dissolution rate in melt than apatite
Mandrara, Zaratiana. "Impact thermique des revêtements en bois sur l’ambiance intérieure des bâtiments : application dans l’habitat traditionnel en France et à Madagascar." Thesis, Lyon, INSA, 2011. http://www.theses.fr/2011ISAL0052/document.
Traditional wood buildings in France and in Madagascar use abundant local forest resources in architecture. Woodcan be considered as renewable and natural material when coming from sustainably managed forest. Using wood in construction contributes significantly in controlling the atmospheric carbon cycle and the emission of greenhouse gas. This study presents the main physical characteristics of wood materials and building systems showing the influence of wood coating on indoor environment. Hygrothermal phenomena across the living space are characterized and presented in this work : the presence of water in the wood, the behavior of equilibrium moisture, heat transfer and mass transfer, the physical parameters of wood material and physical parameters of indoor environment. Thermal comfort is similarly characterised. This work contributes knowledge on the evaluation of interactions between thermal comfort, indoor air and wood coating by means of in situ and laboratory measurements and numerical model simulations
Dandrau, Alain. "La construction en terre dans le monde égéen protohistorique : les matériaux et leurs propriétés." Paris 1, 1997. http://www.theses.fr/1997PA010615.
The most part of the protohistoric aegean sites has given a lot of pieces of earth architecture (pieces of bricks or daub, wall or floor-plasters. . . ). These are usually ignored by the archaeologist. This work, placed between archaeology and archaeometry, want to demonstrate that these construction materials can serve as a source of information of the past societies. The archaeological fragments came from Dikili Tash in Macedonian Greece (5th millenium bc), and from Malia in Crete (2000-1100 bc). The materials used give us informations about architectural structures, technics of building and relations between men and the environment. The analysis have proven that the clay was choosen because of special physical characteristics (waterproof properties for roofs and floors, cohesive earth for walls. . . ). For wall-plasters, physico-chemical analysis were indispensable complements for stylistic and iconographic studies. A typology of plasters, based on function and composition, bring up technological and chronological informations
Martinet, Baptiste. "Caractérisation thermomécanique et identification des endommagements d’un revêtement abradable de compresseurs basse et haute pression en condition de contact sévère." Thesis, Université de Lorraine, 2019. http://www.theses.fr/2019LORR0270.
Reducing gaps between blades and the casing allows an increasing of the aircraft engines effi- ciency. Moreover, blade/casing interactions, mainly due to engine vibrations, may occur. They are localized at the blade tip and may lead to the engine failure. Specific materials called « abradable materials » are used to reduce interactions impact. When an interaction occurs, the abradable ma- terial will be worn preferentialy to the blade and limits the interaction energies. Those materials are studied since many years on experimental devices to develop predictive numerical models. The purpose of this thesis is the experimental characterization of two abradable materials grades from the low-pressure compressor – the AlSi-PE grade – and from the high-pressure compressor – the CoNiCrAlY-hBN grade – on an experimental device. The experimental configuration is simpli- fied and doesn’t take in account the blade’s and casing’s dynamic phenomena. Thermomechanical characterization of two coatings was performed thanks to the correlation between forces, tem- peratures and wear mechanisms. Technological developments allowed representative tests up to 135 m/s and 720 °C. Semi-analytical modeling with Green’s techniques has been used to predict friction temperatures and heat distribution coefficients in the blade and the abradable material. Results have been correlated to an experimental test to approve the model
El, Rassy Elissa. "Development of Methods to Identify Thermophysical Properties of Complex Media." Thesis, Chasseneuil-du-Poitou, Ecole nationale supérieure de mécanique et d'aérotechnique, 2019. http://www.theses.fr/2019ESMA0013.
Advanced materials with complex structures (anisotropic, multilayers and heterogeneous like porous) are increasingly used in many applications, (e.g. automotive, aeronautics, chemical industry, civil and biomedical engineering) due to their advantages, in terms of mechanical and physical properties enhancements. Estimating thermophysical properties of such materials becomes a crucial issue in several applications in order to correctly predict temperature evolution inside these structures and to ensure the control and the modelling of heat transfers through the processes. In this context, the identification of such materials thermophysical properties, has taken from many years, a significant and increasing concern. The main feature of this thesis relies on the devolvement of a direct and simultaneous identification method of the thermal diffusivities of monolayer or multilayer materials using an analytical 3D transient model and a unique and non-intrusive experiment. The proposed method is firstly validated on an isotropic opaque monolayermaterial, then applied and verified on an orthotropic one. The identificationmethod is based on the well-known flash-method experiment whose temperature evolution on the front or rear face on the sample, recorded via an IR camera, is used to identify the unknown parameters. Considering the complexity, and the non-linearity of the inverse problem, a hybrid optimization algorithm combining a stochastic algorithm (Particles Swarm Optimization) and a deterministic one (gradient based), has been chosen. This minimization procedure is applied to fit the observation to the output of a pseudo- analytical model inspired from the thermal quadrupoles approach that predicts the temperature evolution on the front or rear face. The thermal excitation, generated by a CO2 laser, is mimicked by an imposed localized heat flux that may be of Dirac or pulse type. The estimations are compared with values from literature and results obtain from well-established methods. Finally, some improvement of the method are investigated, in terms of time consumption and accuracy, with an optimization of the experiment design (pulse time and intensity, measurement face). The method is then generalised to multi-layer materials, then applied experimentally to a two-layer material. This strategy, which can be considered as a challenging task, is motivated by the impossibility, in some cases, to separate the 2 layers, especially for coatings deposited on substrates which is the last application investigated in this work. A sensitivity analysis is often conducted in order to test the feasibility of the estimation and compare, for two-layer and multilayers materials, several possible configurations in terms of excitation/measurements faces. Pre-evaluation of the overall identification methods and parametric studies are performed using synthetic noisy data generated using the model or a numerical finite element code(pseudo-experiment) to verify the approaches feasibility and robustness. One of the most distinctive features of our approach is that the estimation may be successfully achieved without any a priori knowledge about the shape or the intensity of the excitation. Indeed, besides the simultaneous estimation of the thermal diffusivities, the method predicts the total amount of heat absorbed by the material as well as the space shape of the thermal excitation
Gagnon, Richard. "Optimisation multi-objectif de bâtiments en bois : vers le net-zéro en énergie et en carbone sur la vie du bâtiment." Doctoral thesis, Université Laval, 2018. http://hdl.handle.net/20.500.11794/32726.
Jossé, Camille. "Mélanges de polyoléfines : Influence des procédés de mise en oeuvre et de flammage sur leurs propriétés rhéologiques et mécaniques ainsi que sur leur aptitude à la mise en peinture." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSEI042/document.
Automotive painted exterior car parts have to be made of eco-friendly materials combining fluidity, mechanical properties and visual aspects. In this context, a conventional polypropylene (PP) homopolymer has been extruded and homogeneously blended with an extremely high flow PP, containing reactive species to increase the fluidity of the resulting material. The reactive process was then applied to an automotive high impact PP/Ethylene Propylene Rubber (EPR) formulation and rheological studies allowed us to model the evolution of viscosity as a function of the blend composition. Nevertheless, the increase of fluidity induces a lack of impact resistance. In order to cope with the loss of mechanical properties, the use of a specific thermoplastic elastomers allowed to successfully emphasize impact resilience and strain at break while reaching a viscosity four times lower than the one of the original material. Rheological, thermomechanical and morphological aspects were examined carefully to establish structure-properties relationships. In a second time, a study of the painting of automotive car parts, made of injected polyolefins was carried out. As the hydrophobic nature of polypropylene does not allow a good adhesion between the coating and the polymer surface, the surface activation by flame treatment is required. The effects of different parameters (such as speed, height or air to fuel ratio of the flame) were studied in terms of wettability and coating adhesion. Then, lab-scale as well as pre-industrial experiments revealed defaults of the painted systems when the polymer was highly filled with talc. Then, the impact of the filler on the rheological, thermal and mechanical properties was studied. It was observed that the effects of shear on a formulation where the polymer matrix has no particular physical affinity with the talc surface are responsible of delamination. To enhance the talc-matrix interface, the addition of maleated copolymers pointed out that maleated copolymers increase the level of interactions and lead to a more homogeneous behavior, as revealed by studying both rheological and mechanical properties
Bencheikh, Issam. "Simulation multi-étapes de l’usure des outils de coupe revêtus par une modélisation XFEM/Level-set." Thesis, Université de Lorraine, 2018. http://www.theses.fr/2018LORR0094/document.
In high speed machining, wear resistance of the cutting tools is improved by depositing single or multilayered coatings on their surface. However, the thermomechanical loading generated at the tool-workpiece interface greatly affects the contact zones. For this purpose, several wear modes such as cracking, abrasion, adhesion and delamination of the coating can be occurred. The study of the coatings behavior and their different degradation modes lead to better understanding of their impact on the tool life and machining process under optimal conditions. In this PhD thesis work, a multi-step numerical approach has been proposed to predict wear of the coated cutting tools. This approach involves three main steps. The first is to perform a finite element simulation of the orthogonal cutting for a short time (until the loading stabilization at the tool/workpiece interface). The second step is to recover this loading and use it as an input for the XFEM/Level-set model. The latter allow to take into account the coating layers presence without any need of mesh conforming to the interfaces. As a result, the mesh distortion is avoided when the worn tool profile is updated, as well as the CPU calculation time is drastically reduced. The final step of this approach is to convert the wear rate equation into a nodal displacement, thus representing the cutting tool wear. Based on the experimental tests, a procedure for identifying tool/workpiece contact parameters, and for calibrating the wear equation for each coating layer has been proposed. Experimental trials have been also used to validate the proposed approach
Mohamed, Ibrahim. "Revêtement de Phosphate de calcium sur dioxyde de titane pour des implants métalliques pour des applications médicales." Phd thesis, Université de Strasbourg, 2013. http://tel.archives-ouvertes.fr/tel-00991949.