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1
Davidson, John Lee. "⁵⁷Fe Mössbauer studies of surface interactions in a PVD process." Thesis, Sheffield Hallam University, 1997. http://shura.shu.ac.uk/19536/.
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A critical stage of the combined steered arc and unbalanced magnetron process is the metal ion pre-treatment which improves the adhesion of the TiN coating. In this study, Conversion Electron Mossbauer Spectroscopy (CEMS) has been used to investigate surface interactions in a commercial Arc Bond Sputtering (ABS) coating system. A novel application of the Liljequist theory of CEMS has been used to determine ion etch rates for deposited natural iron on stainless steel substrates, for various Ti ion pre¬treatment processes. The approach has estimated an etch rate of 60 nm min.'1 for samples positioned without substrate rotation at a cathode-sample distance of 250 mm. This has been calculated to correspond to a bias current density of 6.68 Amps m-2. Similar experiments involving modes of rotation yield an average etch rate of approximately 40 nm min.-1 To detect small quantities of iron containing phases formed during a pre-treatment process it has been necessary to enrich substrates with the Mossbauer isotope, 57Fe to achieve greater surface sensitivity. The enrichment used the technique of the deposition of an estimated 25 nm of 57Fe on polished mild steel substrates followed by annealing to generate an 57Fe diffusion profile into the near surface region. A diffusion model has been used to predict the 57Fe depth profile due to the adopted annealing process parameters. Verification of the estimated thickness of the deposited 57Fe overlayer and the diffusion profile has been provided by SIMS and SNMS. Using the 57Fe enriched mild steel samples, CEMS has investigated the formation of iron- titanium phases after a typical industrial ten minute pre-treatment process using substrate rotation, at a substrate bias voltage of -1200 V. Significant phase formation of both crystalline Fe[x]Ti[1-x] and amorphous Fe[x]Ti[1-x] have been identified. The formation of the crystalline phase has been confirmed by XRD. Using a model of the 57Fe isomer shift dependence of x, in amorphous alloys yielded x=0.31 +/-0.08 for Fe[x]Ti[1-x] Further experiments using an estimated 25 nm of 57Fe deposited on mild steel without annealing, showed the presence of magnetite and a small quantity of crystalline FeTi for a 25 s pre¬treatment process. After a 300 s pre-treatment time the oxide layer is removed and significant quantities of both crystalline and amorphous FeTi are formed. CEMS has also showed increased 57Fe removal at a 6 x 10-5 mbar Ar operating pressure within the coating chamber compared with a pre-treatment performed at a higher Ar pressure of 3 x 10-3 mbar, showing the greater effect of the Ti ion etching under these conditions. During the experiments performed at different Ar pressures, CEMS also identified iron carbonitride phases. Similar phases have also been identified in the early growth stages of a compound layer in a process performed using a modified Balzers coating system. CEMS has proved to be a powerful technique, enabling the investigation of surface interaction phenomena occurring in the near surface region of 57Fe enriched substrates treated by Physical Vapour Deposition (PVD) processes. The information provided by the technique makes it strategically important in the future research of interface regions generated by PVD processes.
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Macak, Eva. "Electron microscopy of sharp edges and corners coated by ion-assisted PVD." Thesis, Sheffield Hallam University, 2003. http://shura.shu.ac.uk/19991/.
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The thesis examines ion-assisted physical-vapour deposition (PVD) of thin coatings on non-flat three-dimensional samples, concentrating on the case of free-standing edges and comers. Changes in the electric field in the vicinity of sharp edges lead to local changes in the ion bombardment (ion flux and angle of incidence) which can significantly affect the ion-surface interaction and thus the properties and the performance of the coatings growing in the edge region. This work presents a detailed electron microscopy study of the edge-related changes in the coating properties and develops a physical model to explain and quantify the effects. The problem is studied on a system typical for industrial coating of cutting tools used in dry high speed cutting: TiAlN-type coatings (TiAlN/VN and TiAlCrYN) deposited on wedge-shaped samples by closed-field unbalanced magnetron sputtering (UBM), using high-flux, low-energy Ar+ ion irradiation (J[i]/J[me]~4, E[i] = 75-150 eV). The morphology and composition of the coatings in the edge region, as a function of the edge geometry (angle and radius of curvature) and the deposition conditions (substrate bias), is studied using scanning electron microscopy combined with energy-dispersive X-ray spectroscopy (SEM+EDX). The internal structure of the coatings growing on sharp edges is examined by transmission electron microscopy (TEM). A detailed theoretical analysis of the effects, based on the simulations of the plasma sheath around the samples and the resulting ion bombardment distribution, is presented. A direct relationship between the experimentally observed magnitude and spatial extent of the changes in the edge region and the simulated characteristics of the plasma sheath around the edges is shown.
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Abd, Rahman M. N. "Modelling of physical vapour deposition (PVD) process on cutting tool using response surface methodology (RSM)." Thesis, Coventry University, 2009. http://curve.coventry.ac.uk/open/items/cca436cf-b72b-c899-ef02-bd522b0d7ec5/1.
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The Physical Vapour Deposition (PVD) magnetron sputtering process is one of the widely used techniques for depositing thin film coatings on substrates for various applications such as integrated circuit fabrication, decorative coatings, and hard coatings for tooling. In the area of coatings on cutting tools, tool life can be improved drastically with the application of hard coatings. Application of coatings on cutting tools for various machining techniques, such as continuous and interrupted cutting, requires different coating characteristics, these being highly dependent on the process parameters under which they were formed. To efficiently optimise and customise the deposited coating characteristics, PVD process modelling using RSM methodology was proposed. The aim of this research is to develop a PVD magnetron sputtering process model which can predict the relationship between the process input parameters and resultant coating characteristics and performance. Response Surface Methodology (RSM) was used, this being one of the most practical and cost effective techniques to develop a process model. Even though RSM has been used for the optimisation of the sputtering process, published RSM modelling work on the application of hard coating process on cutting tool is lacking. This research investigated the deposition of TiAlN coatings onto tungsten carbide cutting tool inserts using PVD magnetron sputtering process. The input parameters evaluated were substrate temperature, substrate bias voltage, and sputtering power; the out put responses being coating hardness, coating roughness, and flank wear (coating performance). In addition to that, coating microstructures were investigated to explain the behaviour of the developed model. Coating microstructural phenomena assessed were; crystallite grain size, XRD peak intensity ratio I111/I200 and atomic number percentage ratio of Al/Ti. Design Expert 7.0.3 software was used for the RSM analysis. Three process models (hardness, roughness, performance) were successfully developed and validated. The modelling validation runs were within the 90% prediction interval of the developed models and their residual errors compared to the predicted values were less than 10%. The models were also qualitatively validated by justifying the behaviour of the output responses (hardness, roughness, and flank wear) and microstructures (Al/Ti ratio, crystallographic peak ratio I111/1200, and grain size) with respect to the variation of the input variables based on the published work by researchers and practitioners in this field. The significant parameters that influenced the coating hardness, roughness, and performance (flank wear) were also identified. Coating hardness was influenced by the substrate bias voltage, sputtering power, and substrate temperature; coating roughness was influenced by sputtering power and substrate bias; and coating performance was influenced by substrate bias. The analysis also discovered that there was a significant interaction between the substrate temperature and the sputtering power which significantly influenced coating hardness, roughness, and performance; this interaction phenomenon has not been reported in previously published literature. The correlation study between coating characteristics, microstructures and the coating performance (flank wear) suggested that the coating performance correlated most significantly to the coating hardness with Pearson coefficient of determination value (R2) of 0.7311. The study also suggested some correlation between coating performance with atomic percentage ratio of Al/Ti and grain size with R2 value of 0.4762 and 0.4109 respectively.
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Gulizia, Stefan. "Soldering in high pressure die casting (HPDC) performance evaluation and characterisation of physical vapour deposition (PVD) coatings /." Swinburne Research Bank, 2008. http://hdl.handle.net/1959.3/39640.
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Thesis (MEng) - School of Engineering and Science, Swinburne University of Technology, 2008.Thesis submitted for the degree of Master of Engineering, School of Engineering and Science, Swinburne University of Technology, 2008. Typescript. Includes bibliographical references (p. 98-101).
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Pereira, Vitor Emanuel M. Loureiro S. "Computer model to predict electron beam-physical vapour deposition (EB-PVD) and thermal barrier coating (TBC) deposition on substrates with complex geometry." Thesis, Cranfield University, 2000. http://dspace.lib.cranfield.ac.uk/handle/1826/5714.
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For many decades gas turbine engineers have investigated methods to improve engine efficiency further. These methods include advances in the composition and processing of materials, intricate cooling techniques, and the use of protective coatings. Thermal barrier coatings (TBCs) are the most promising development in superalloy coatings research in recent years with the potential to reduce metal surface temperature, or increase turbine entry temperature, by 70-200°C. In order for TBCs to be exploited to their full potential, they need to be applied to the most demanding of stationary and rotating components, such as first stage blades and vanes. Comprehensive reviews of coating processes indicate that this can only be achieved on rotating components by depositing a strain-tolerant layer applied by the electron beam-physical vapour deposition (EB-PVD) coating process. A computer program has been developed in Visual c++ based on the Knudsen cosine law and aimed at calculating the coating thickness distribution around any component, but typically turbine blades. This should permit the controlled deposition to tailor the TBC performance and durability. Various evaporation characteristics have been accommodated by developing a generalised point source evaporation model that involves real and virtual sources. Substrates with complex geometry can be modelled by generating an STL file from a CAD package with the geometric information of the component, which may include shadow-masks. Visualisation of the coated thickness distributions around components was achieved using OpenGL library functions within the computer model. This study then proceeded to verify the computer model by first measuring the coating thickness for experimental trial runs and then comparing the calculated coating thickness to that measured using a laboratory coater. Predicted thickness distributions are in good agreement even for the simplified evaporation model, but can be improved further by increasing the complexity of the source model.
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Branger, Vincent. "Analyse microstructurale et mécanique de films minces métalliques obtenus par PVD [physical vapor deposition]." Poitiers, 1998. http://www.theses.fr/1998POIT2258.
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Un grand nombre de travaux experimentaux ont montre que les materiaux sous forme de films minces peuvent admettre des contraintes qui sont tres largement superieures a la limite elastique de ces memes materiaux a l'etat massif. La microstructure particuliere (hors d'equilibre, nanograins) de ces films est generalement avancee pour argumenter les observations experimentales. Ainsi, pour mieux comprendre les relations etroites qui existent entre la structure, les proprietes mecaniques et les processus d'elaboration des films minces, il est necessaire de mener de front une etude a la fois sur la microstructure et les aspects mecaniques intrinseques du film tels que les contraintes residuelles et le module elastique. Pour atteindre cet objectif, nous avons mis en uvre un ensemble de techniques d'analyse variees et complementaires (diffraction des rayons x, spectroscopie mecanique) qui permet d'acceder aux defauts et aux contraintes dans les regions intra granulaires mais aussi inter granulaires (joints de grains) de films minces metalliques (ag, pt, ni, cu, mo et cu-mo). Nous avons confirme l'influence de l'energie des atomes deposes sur la genese des contraintes dans ces films minces et etabli le lien etroit existant entre les defauts et l'etat mecanique au travers de modeles simples decrits par certains auteurs dans la litterature. Lors de l'etude de la stabilite des solutions solides cu-mo, nous avons montre le role important joue par les contraintes residuelles et determine par des techniques variees (spectroscopie mecanique, acoustique picoseconde et diffusion brillouin) le module d'young de ces films. Enfin, une premiere etude par microscopie en champ proche des decollements spontanes inities par les contraintes dans ces films minces nous a permis de determiner l'energie d'adhesion de l'ensemble film/substrat.
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Schmitz, Tobias [Verfasser], and Jürgen [Gutachter] Groll. "Functional coatings by physical vapor deposition (PVD) for biomedical applications / Tobias Schmitz ; Gutachter: Jürgen Groll." Würzburg : Universität Würzburg, 2017. http://d-nb.info/1126419125/34.
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Ivchenko, Dmitrii. "Modeling and design of a physical vapor deposition process assisted by thermal plasma (PS-PVD)." Thesis, Limoges, 2018. http://www.theses.fr/2018LIMO0099/document.
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Le procédé de dépôt physique en phase vapeur assisté par plasma thermique (PS-PVD) consiste à évaporer le matériau sous forme de poudre à l’aide d’un jet de plasma d’arc soufflé pour produire des dépôts de structures variées obtenus par condensation de la vapeur et/ou dépôt des nano-agrégats. Dans le procédé de PS-PVD classique, l’intégralité du traitement du matériau est réalisée dans une enceinte sous faible pression, ce qui limite les phénomènes d’évaporation ou nécessite d’utiliser des torches de puissance importante. Dans ce travail, une extension du procédé de PS-PVD conventionnel à un procédé à deux enceintes est proposée puis explorée par voie de modélisation et de simulation numérique : la poudre est évaporée dans une enceinte haute pression (105 Pa) reliée par une tuyère de détente à une enceinte de dépôt basse pression (100 ou 1 000 Pa), permettant une évaporation énergétiquement plus efficace de poudre de Zircone Yttriée de granulométrie élevée, tout en utilisant des torches de puissance raisonnable. L’érosion et le colmatage de la tuyère de détente peuvent limiter la faisabilité d’un tel système. Aussi, par la mise en oeuvre de modèles numériques de mécaniquedes fluides et basé sur la théorie cinétique de la nucléation et de la croissance d’agrégats, on montre que, par l’ajustement des dimensions du système et des paramètres opératoires ces deux problèmes peuvent être contournés ou minimisés. En particulier, l’angle de divergence de la tuyère de détente est optimisé pour diminuer le risque de colmatage et obtenir le jet et le dépôt les plus uniformes possibles à l'aide des modèles susmentionnés, associés à un modèle DSMC (Monte-Carlo) du flux de gaz plasmagène raréfié. Pour une pression de 100 Pa, les résultats montrent que la barrière thermique serait formée par condensation de vapeur alors que pour 1 000 Pa, elle serait majoritairement formée par dépôt de nano-agrégatsPlasma Spray Physical Vapor Deposition (PS-PVD) aims to substantially evaporate material in powder form by means of a DC plasma jet to produce coatings with various microstructures built by vapor condensation and/or by deposition of nanoclusters. In the conventional PS-PVD process, all the material treatment takes place in a medium vacuum atmosphere, limiting the evaporation process or requiring very high-power torches. In the present work, an extension of conventional PS-PVD process as a two-chamber process is proposed and investigated by means of numerical modeling: the powder is vaporized in a high pressure chamber (105 Pa) connected to the low pressure (100 or 1,000 Pa) deposition chamber by an expansion nozzle, allowing more energetically efficient evaporation of coarse YSZ powders using relatively low power plasma torches. Expansion nozzle erosion and clogging can obstruct the feasibility of such a system. In the present work, through the use of computational fluid dynamics, kinetic nucleation theory and cluster growth equations it is shown through careful adjustment of system dimensions and operating parameters both problems can be avoided or minimized. Divergence angle of the expansion nozzle is optimized to decrease the clogging risk and to reach the most uniform coating and spray characteristics using the aforementioned approaches linked with a DSMC model of the rarefied plasma gas flow. Results show that for 100 Pa, the thermal barrier coating would be mainly built from vapor deposition unlike 1,000 Pa for which it is mainly built by cluster deposition
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Kabir, Humaun Md. "Beeinflussung und Charakterisierung von Schichteigenschaften metallisierter Textilien." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2004. http://nbn-resolving.de/urn:nbn:de:swb:14-1107163601832-76149.
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Mit dünnen Schichten, die mittels der PVD-Dünnschichttechnik auf Textilien aufgebracht werden, wird eine neue Möglichkeit zur Veredlung von Textilien eröffnet. Die Plasmabehandlung bewirkt eine Veränderung der Substratoberfläche in zwei Richtungen. Einerseits werden die Oberflächenspannung und die Adhäsion beeinflusst und andererseits kommt es zum Aufrauhen der Oberfläche. Die Zunahme der Oberflächenrauheit, hat drei Auswirkungen. Erstens bietet die größere Fläche mehrere molekulare Aufstellungsorte für die Wechselwirkung zwischen dem Adhärens und dem Adhäsiv an. Zweitens wird das mechanische Ineinandergreifen (Interlocking) zwischen dem Adhäsiv und Adhärens stärker und drittens kommt es zum Entfernen der schwachen Grenzschichten auf der Proben-Oberfläche. Die Vorbehandlung mittels Fluorierung führt ebenso wie die Niederdruckplasmabehandlung mit Sauerstoff bei Gewebe aus synthetische Fasern grundsätzlich zu einer Verbesserung der Festigkeit im Verbund. Beide Vorbehandlungsmethoden stellen alternative, notwendige Verfahren zur Haftungsverbesserung dar. Im Allgemeinen haften die Schichten bei besputterten Proben gegenüber bedampften Proben besser. Eine wesentlich geringere Haftung weisen die Schichten auf den unbehandelten Substraten auf. Neben Untersuchungen zur Haftbeständigkeit der Schichten erfolgen Untersuchungen zur Leitfähigkeit und zur elektromagnetischen Schirmdämpfung der Substrate. Die Oberflächenwiderstände werden sowohl von der Konstruktion der textilen Fläche als auch von den Beschichtungszeiten beeinflusst. Erwartungsgemäß führen längere Beschichtungszeiten zu sinkenden Oberflächenwiderständen.
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Hagerty, Phillip. "Physical Vapor Deposition of Materials for Flexible Two Dimensional Electronic Devices." University of Dayton / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1460739765.
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Ondráček, Michal. "Tvorba motivů tenkovrstvými metodami." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2014. http://www.nusl.cz/ntk/nusl-220968.
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The master’s thesis deals with the theory of thin film technology, especially creating these layers. The work includes the distribution of vacuum deposition techniques for physical (PVD) and chemical (CVD). The main aim is to create a theme in different ways of implementation by using magnetron sputtering device, and these motives evaluated in terms of the quality of sputtering.
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Rezanka, Stefan [Verfasser], Robert [Akademischer Betreuer] Vaßen, and Detlev [Akademischer Betreuer] Stöver. "Abscheidung von Wärmedämmschichtsystemen mit dem Plasma Spray-Physical Vapor Deposition- (PS-PVD-) Prozess / Stefan Rezanka. Gutachter: Robert Vaßen ; Detlev Stöver." Bochum : Ruhr-Universität Bochum, 2016. http://d-nb.info/1082425850/34.
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He, Wenting [Verfasser], Robert [Gutachter] Vaßen, and Alfred [Gutachter] Ludwig. "Deposition mechanisms of thermal barrier coatings (TBCs) manufactured by plasma spray-physical vapor deposition (PS-PVD) / Wenting He ; Gutachter: Robert Vaßen, Alfred Ludwig ; Fakultät für Maschinenbau." Bochum : Ruhr-Universität Bochum, 2017. http://d-nb.info/115050983X/34.
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Doležalová, Petra. "Vlastnosti povlaků řezných nástrojů ze slinutého karbidu." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2013. http://www.nusl.cz/ntk/nusl-230904.
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Diploma thesis is divided into two parts. The first part is focused on theoretical description of coating methods, on currently used coatings, their properties and it is also focused on description of methods, which are used for analyzing each property. The second part focuses on testing of coatings and analyzing of the values obtained from experiments. The aim of this thesis is then to compare the properties of the tested coatings.
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Constable, Christopher Paul. "Raman microscopic studies of PVD deposited hard ceramic coatings." Thesis, Sheffield Hallam University, 2000. http://shura.shu.ac.uk/19498/.
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PVD hard ceramic coatings grown via the combined cathodic arc/unbalance magnetron deposition process were studied using Raman microscopy. Characteristic spectra from binary, multicomponent, multilayered and superlattice coatings were acquired to gain knowledge of the solid-state physics associated with Raman scattering from polycrystalline PVD coatings and to compile a comprehensive spectral database. Defect-induced first order scattering mechanisms were observed which gave rise to two pronounced groups of bands related to the acoustical (150-300cm[-1]) and optical (400-750cm[-1]) parts of the phonon spectrum. Evidence was gathered to support the theory that the optic modes were mainly due to the vibrations of the lighter elements and the acoustic modes due to the vibrations of the heavier elements within the lattice. A study into the deformation and disordering on the Raman spectral bands of PVD coatings was performed. TiAIN and TiZrN coatings were intentionally damaged via scratching methods. These scratches were then analysed by Raman mapping, both across and along, and a detailed spectral interpretation performed. Band broadening occurred which was related to "phonon relaxation mechanisms" as a direct result of the breaking up of coating grains resulting in a larger proportion of grain boundaries per-unit-volume. A direct correlation of the amount of damage with band width was observed. Band shifts were also found to occur which were due to the stresses caused by the scratching process. These shifts were found to be the largest at the edges of scratches. The Raman mapping of "droplets", a defect inherent to PVD deposition processes, found that higher compressive stresses and large amounts of disorder occurred for coating growth onto droplets. Strategies designed to evaluate the ability of Raman microscopy to monitor the extent of real wear on cutting tools were evaluated. The removal of a coating layer and subsequent detection of a base layer proved successful. This was then expanded to real wear situations in which tools were monitored after 3,6,12,64,120 and 130 minutes-in-cut. A PCA chemometrics model able to distinguish between component layers and oxides was developed. Raman microscopy was found to provide structural and compositional information on oxide scales formed on the surfaces of heat-treated coatings. Wear debris, generated as a consequence of sliding wear tests on various coatings, was also found to be primarily oxide products. The comparison of the oxide types within the debris to those formed on the surface of the same coating statically oxidised, facilitated a contact temperature during sliding to be estimated. Raman microscopy, owing to the piezo-spectroscopic effect, is sensitive to stress levels. The application of Raman microscopy for the determination of residual compressive stresses within PVD coatings was evaluated. TiAlN/VN superlattice coatings with engineered stresses ranging -3 to -11.3 GPa were deposited onto SS and HSS substrates. Subsequent Raman measurements found a correlation coefficient of 0.996 between Raman band position and stress (determined via XRD methods). In addition, there was also a similar correlation coefficient observed between hardness and Raman shift (cm-1). The application of mechanical stresses on a TiAlCrN coating via a stress rig was investigated and tensile and compressive shifts were observed.
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Bernier, Jeremy Scott. "Evolution and Characterization of Partially Stabilized Zirconia (7wt% Y2O3) Thermal Barrier Coatings Deposited by Electron Beam Physical Vapor Deposition." Digital WPI, 2002. https://digitalcommons.wpi.edu/etd-theses/826.
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Thermal barrier coatings (TBCs) of ZrO2-7wt% Y2O3 were deposited by electron beam physical vapor deposition (EB-PVD) onto stationary flat plates and cylindrical surfaces in a multiple ingot coater. Crystallographic texture, microstructure, and deposition rate were investigated in this thesis. The crystallographic texture of EB-PVD TBCs deposited on stationary flat surfaces has been experimentally determined by comparing pole figure analysis data with actual column growth angle data. It was found that the TBC coating deposited directly above an ingot exhibits <220> single crystal type crystallographic texture. Coatings deposited between and off the centerline of the ingots the exhibited a <311>-type single crystal texture. For coatings deposited in the far corners of the coating chamber either a <111> fiber texture or a <311> single crystal type texture existed. The crystallographic texture of EB-PVD TBCs deposited on cylindrical surfaces was characterized using x-ray diffraction (XRD) at different angular positions on the cylinder substrate. XRD results revealed that crystallographic texture changes with angular position. Changes in crystallographic texture are attributed to the growth direction of the columns and substrate temperature. Growth direction is controlled by the direction of the incoming vapor flux (i.e. vapor incidence angle), in which competition occurs between crystallites growing at different rates. The fastest growing orientation takes over and dominates the texture. Substrate temperature variations throughout the coating chamber resulted in different growth rates and morphology. Morphology differences existed between cylindrical and flat plate surfaces. Flat cross sectional surfaces of the coatings exhibited a dense columnar structure in which the columns grew towards the closest vapor source. Surface features were found to be larger for coatings deposited directly above an ingot than coatings deposited away from the ingots. Morphological differences result from substrate temperature changes within the coating chamber, which influences growth kinetics of the coating. Cylindrical surfaces revealed a columnar structure in which columns grew towards the closest vapor. Porosity of the coating was found to increase when the angular position changed from the bottom of the cylinder. Change in angular position also caused the column diameter to decreases. Morphology changes are attributed to self-shadow effects caused by the surface curvature of the cylinder and vapor incidence angle changes. Overall, the microstructure and crystallographic texture of EB-PVD coatings was found to depend on the position in the coating chamber which was found to influence substrate temperature, growth directions, and shadowing effects. The coating thickness profiles for EB-PVD TBCs deposited on stationary cylinders have been experimentally measured and theoretically modeled using Knudsen's cosine law of emissions. A comparison of the experimental results with the model reveals that the model must to be modified to account for the sticking coefficient as well as a ricochet factor. These results are also discussed in terms of the effects of substrate temperature on the sticking coefficient, the ricochet factor, and coating density.
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Ashiuchi, Edgar Sobral. "Efeitos do tratamento criogênico profundo e do revestimento de CrN por PVD no na microabrasão da liga de alumínio AA 6101-T4." reponame:Repositório Institucional da UnB, 2015. http://repositorio.unb.br/handle/10482/20193.
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Tese (doutorado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Mecânica, 2015.Submitted by Fernanda Percia França (fernandafranca@bce.unb.br) on 2015-11-20T19:59:26Z No. of bitstreams: 1 2015_EdgarSobralAshiuchi.pdf: 4822357 bytes, checksum: 0a5b84f109f0c56b9d9bd06d784e6ea3 (MD5)
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Este trabalho tem como principal objetivo investigar os efeitos do tratamento criogênico profundo quanto à microabrasão na liga de alumínio laminado AA 6101-T4 com e sem o revestimento de CrN depositado por PVD. O material tal como recebido foi utilizado como referência de desempenho em ensaios de resistência ao desgaste microabrasivo para amostras que receberam o tratamento criogênico, o revestimento de CrN ou as combinações de ambos. O material tratado criogenicamente apresentou aumento relativo na resistência ao desgaste da ordem de 35%. Com uma combinação específica do tratamento criogênico profundo e do revestimento de filme fino de CrN, a resistência ao desgaste obteve incremento da ordem de 81%. Esse resultado da combinação do tratamento criogênico e do revestimento de CrN foi substancialmente superior aos obtidos para os materiais que receberam apenas um deles. Levando em consideração os mecanismos de desgaste manifestados no sistema tribológico, a dureza não demonstrou acompanhar o acréscimo da resistência ao desgaste. Estruturas nanométricas tais como aglomerados ou zonas de Guinier-Preston (GP) exibiram maior concentração nas amostras tratadas criogenicamente. De acordo com este trabalho, apenas a presença de tais nanoestruturas pôde ser associada ao aumento da resistência ao desgaste com a aplicação do tratamento criogênico profundo. Esta tese explora esse tipo de beneficiamento além dos limites da sua habitual aplicação para o aço. _______________________________________________________________________________________________ ABSTRACT
This work aimed to investigate the effects of deep cryogenic treatment with respect to the abrasion in rolled aluminum alloy AA 6101-T4 with and without the CrN coating deposited by PVD. The material as received was used as a performance benchmark in microabrasive wear resistance test for samples receiving the cryogenic treatment, the CrN coatings or combinations of both. The cryogenically treated material presented relative increase in wear resistance of the order of 35%. With a specific combination of deep cryogenic treatment and the thin CrN film coating, the wear resistance was an increase of approximately 81%. This results from the combination of the cryogenic treatment and CrN coating was substantially higher than those obtained for the materials that received only one of them. Taking into account the wear mechanisms manifested in the tribological system, the hardness did not show follow the wear resistance increase. Nanoscale structures such as clusters or Guinier-Preston(GP) zones exhibited highest concentration in the samples treated cryogenically. According to this work, only the presence of such nanostructures could be associated with increased wear resistance for the material cryogenic treated. This thesis explores the deep cryogenic treatment beyond the limits of their usual application for steel.
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鈴木, 賢治, Kenji SUZUKI, 一秀 松本, Kazuhide MATSUMOTO, 貴博 久保, Takahiro KUBO, 修太郎 町屋, et al. "高エネルギー反射光によるEB-PVD遮熱コーティングの残留応力分布の解析." 日本機械学会, 2005. http://hdl.handle.net/2237/9130.
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Schlieter, Antje, Christoph Leyens, Tesuya Takahashi, Mona Naderi, Peter Jaschinski, and Rainer Cremer. "Nanolaminare Schichtsysteme für Umformwerkzeuge." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2013. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-105309.
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Abstract der Posterpräsentation:
PVD-Beschichtungsverfahren (Physical Vapour Deposition) haben sich aufgrund der vielfältigen Möglichkeiten, unterschiedliche Oberflächeneigenschaften von dünnen Schichten mit fast jedem Volumenmaterial (Substrat) kombinieren zu können, etabliert. Durch die definierte Einstellung der Prozessparameter (z. B. Energiezufuhr, Druck, Gaszusammensetzung) können Schichten gemäß den spezifischen Anforderungen des Einsatzzweckes angepasst und optimiert werden. Selbst widersprechende Eigenschaften wie extreme Härte und Flexibilität lassen sich miteinander kombinieren.
Zielsetzung des im Rahmen des BMBF-Programms „KMU-innovativ: Nanotechnologie“ (Nanochance) geförderten Forschungsvorhabens ist die Entwicklung einer neuartigen Kombination aus plasmagestützter Bogenentladung und gepulster HPPMS-Sputterabscheidung (High Power Pulsed Magnetron Sputtering) für die Herstellung von schadenstoleranten Schichten auf Umformwerkzeugen. Durch diese Kombination soll zum einen die Qualität bestehender nanokristalliner Schichtsysteme signifikant verbessert sowie eine Vielzahl neuer Schichtsysteme mit bislang nicht erreichten Eigenschaften synthetisiert werden.
Ein derzeit untersuchtes Schichtsystem besteht aus einer konventionellen Hartstoffschicht mit sehr hoher Formbeständigkeit und einer weniger als fünf Mikrometer dünnen Deckschicht aus einer Cr2AlC-MAX-Phase, die chemisch und thermisch beständig ist und einen sehr geringen Reibverschleiß hat.
Die Beschichtung erfolgt in einer umgerüsteten industriellen PVD-Beschichtungsanlage im Technikum der KCS Europe GmbH. Durch in-situ Plasmaanalysen sowie mikrostrukturelle und mechanische Charakterisierungen der unterschiedlich hergestellten Schichtsysteme durch die TU Dresden wird die Korrelation zwischen technischen Beschichtungsparametern, Plasmaparametern sowie Schichtstruktur und Schichteigenschaften erarbeitet. Damit wird ein tiefgreifendes Verständnis der Abscheidemechanismen von nanokristallinen Schichtsystemen und eine Beschleunigung des Entwicklungsprozesses möglich.
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Zhang, Bochun. "Failure Mechanism Analysis and Life Prediction Based on Atmospheric Plasma-Sprayed and Electron Beam-Physical Vapor Deposition Thermal Barrier Coatings." Thesis, Université d'Ottawa / University of Ottawa, 2017. http://hdl.handle.net/10393/35709.
Full textAbstract:
Using experimentally measured temperature-process-dependent model parameters, the failure analysis and life prediction were conducted for Atmospheric Plasma Sprayed Thermal Barrier Coatings (APS-TBCs) and electron beam physical vapor deposition thermal barrier coatings (EB-PVD TBCs) with Pt-modified -NiAl bond coats deposited on Ni-base single crystal superalloys. For APS-TBC system, a residual stress model for the top coat of APS-TBC was proposed and then applied to life prediction. The capability of the life model was demonstrated using temperature-dependent model parameters. Using existing life data, a comparison of fitting approaches of life model parameters was performed. The role of the residual stresses distributed at each individual coating layer was explored and their interplay on the coating’s delamination was analyzed. For EB-PVD TBCs, based on failure mechanism analysis, two newly analytical stress models from the valley position of top coat and ridge of bond coat were proposed describing stress levels generated as consequence of the coefficient of thermal expansion (CTE) mismatch between each layers. The thermal stress within TGO was evaluated based on composite material theory, where effective parameters were calculated. The lifetime prediction of EB-PVD TBCs was conducted given that the failure analysis and life model were applied to two failure modes A and B identified experimentally for thermal cyclic process. The global wavelength related to interface rumpling and its radius curvature were identified as essential parameters in life evaluation, and the life results for failure mode A were verified by existing burner rig test data. For failure mode B, the crack growth rate along the topcoat/TGO interface was calculated using the experimentally measured average interfacial fracture toughness.
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Barutcu, Burcu. "The Design And Production Of Interference Edge Filters With Plasma Ion Assisted Deposition Technique For A Space Camera." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614574/index.pdf.
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Interference filters are multilayer thin film devices. They use interference effects between
the incident and reflected radiation waves at each layer interface to select wavelengths. The
production of interference filters depend on the precise deposition of thin material layers on
substrates which have suitable optical properties. In this thesis, the main target is to design
and produce two optical filters (short-pass filter and long-pass filter) for the CCDs that will
be used in the electronics of a space camera. By means of these filters, it is possible to take
image in different bands (RGB and NIR) by identical two CCDs. The filters will be fabricated
by plasma ion-assisted deposition technique.
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Morken, Michael Owen Morken. "An Investigation Into The Feasibility Of Transparent Conductive Coatings At Visimax Technologies." Case Western Reserve University School of Graduate Studies / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=case1496835960043161.
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Apreutesei, Mihai. "Temperature impact on thermal evolution of advanced PVD ceramic and metallic glass thin films : Physico-chemical and microstructural analysis." Thesis, Lyon, INSA, 2015. http://www.theses.fr/2015ISAL0009/document.
Full textAbstract:
Ces dernières années, les exigences de l'industrie dans le développement de nouveaux matériaux fonctionnels en mesure de résister aux conditions difficiles pendant l'opération d'usinage sont en constante augmentation. Les chercheurs doivent donc trouver de nouvelles solutions pour répondre aux besoins industriels de plus en plus sévères. L’utilisation de revêtement protecteur à la surface de l’outil de coupe est une solution très efficace. Des nouveaux matériaux architecturés sont étudiés pour leurs propriétés mécaniques, physiques et chimiques uniques assurant une résistance aux dégradations de surface dues à la corrosion, l'usure, le frottement; en particulier lorsque ces outils sont utilisés dans des environnements hostiles. Dans le cadre de cette thèse de doctorat, l'influence de la température sur la stabilité structurale de deux types de films minces déposés par PVD a été étudiée. Des films céramiques et de verre métallique ont été envisagés. Afin de préparer et optimiser ces films, le projet s’est axé sur l'étude de l'influence des conditions de dépôt sur les caractéristiques de croissance du film: composition chimique, structure, morphologie, puis sur les changements ultérieurs des principales propriétés des films minces, à savoir la résistance à l’oxydation et à la cristallisation lors de leur utilisation à hautes températures. Une démarche multi-échelle a été développée pour caractériser au mieux les couches. La première partie du travail est liée aux revêtements céramiques à base de CrN pour donner de nouvelles fonctionnalités et améliorer la surface des outils de coupe dans le but essentiel d'accroître leur durée de vie. La seconde partie du manuscrit est dédiée aux films minces de verres métalliques de Zr-Cu préparés par un procédé de co-pulvérisation magnétron PVD. Le but de cette partie consiste en l’étude de la relation entre la structure amorphe de ces films et leurs propriétés mécaniques. La conservation du caractère amorphe de ces films en température présente également un caractère essentiel. Les verres métalliques ont récemment attiré un fort intérêt car ils présentent des propriétés mécaniques intéressantes à température ambiante. Ils présentent, de ce fait, un grand potentiel pour des applications d'ingénierie en raison de leurs caractéristiques mécaniques et physico-chimiques uniques (haute limite élastique, résistance à la corrosion ...). Pour relier les propriétés mécaniques des couches à l’évolution de leurs microstructures, une partie importante de ce travail a porté sur l’observation de l’évolution de la couche au cours du chauffage au moyen de techniques de caractérisation in situ. Les films minces proposés au cours de ce travail peuvent être envisagées pour un large gamme d’application dans l’ingénierie de surface pour protéger les surfaces et améliorer la durée de vie des matériauxIn the recent years the industrial requirements to develop new functional materials able to overcome the severe conditions during machining operation are continuously increasing. Researchers then must find novel solutions to respond to their severe industrial requirements. To coat the tool surface with advanced coatings is the most efficient solution. New nanostructured materials may nowadays exhibit unique mechanical, physical and chemical properties ensuring notable degradation resistance where the surface protection of materials against corrosion, wear, friction or oxidation is a key issue, particularly when operating in hostile environments. Within the scope of this Ph.D. thesis the influence of the temperature on the structural stability of two different PVD ceramic and metallic glass thin films is proposed. The main goal consists in the development of two distinct classes of thin films, with a wide range of properties. In order to prepare these films, the project will be focused on the study on the influence of PVD deposition conditions in the particular film’s growth characteristics: chemical composition, structure, morphology and the subsequent changes in the main properties of the thin films, namely oxidation and crystallization resistance, especially. For that purpose we adopted the multiscale approach. The first part is related to the ceramic CrN-based coatings to give new functionalities and improve the tools’ surface with the primary aim to increase their lifetime. Secondly, new protective materials able to better protect the exposed surfaces against high temperature oxidation have been proposed, namely CrAlN and CrAlYN coatings as will be evidenced in this manuscript. The second part of the manuscript is dedicated to the innovative Zr-Cu thin films metallic glasses prepared by a PVD magnetron co-sputtering method with the objective to investigate the amorphization ability and their structural properties. Their excellent properties at room temperature have recently attracted attention as a new class of materials with great potential for engineering applications due to unique mechanical and physico-chemical characteristics (high elastic strain limit, corrosion resistance…). Finally, an important approach during the course of this thesis was the real time observation of the structure and surface modifications during heating by means of in situ methods. The thin films proposed during the course of the work could be straightforward used as surface engineering solutions to protect and extend the lifetime of the materials and components
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Dieudonné, Belto. "Guides d’onde en verres et vitrocéramiques fluorés dopés terre rare élaborés par PVD pour l’émission dans le visible et la conversion de fréquence." Thesis, Le Mans, 2012. http://www.theses.fr/2012LEMA1023/document.
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Le projet s’inscrit dans le développement de sources lasers RGB miniaturisées pour l’affichage et la vidéoprojection, la conversion de fréquence dans les cellules solaires.Les verres fluorés ZLAG (ZrF4-LaF3-AlF3-GaF3) codopés terres rares ont été considérés. Ce verre possède une faible énergie de phonon, une forte solubilité des terres rares et peut être fabriqué en couche mince par la technique PVD. Il est de plus le précurseur de vitrocéramiques transparentes. On a observé dans les verres massifs et les guides d’onde des émissions bleue, orange et rouge avec un codopage Pr3+-Yb3+, bleue et rouge avec un co-dopage Tm3+-Yb3+. L’émission RGB dans les verres tri-dopés Tm3+-Er3+-Yb3+ semble prometteuse. Par ailleurs, la vitro-céramisation a permis d’augmenter de plus de 30% les sections efficaces d’absorption des ions Pr3+ et Yb3+.Une efficacité de transfert de 92% a été obtenue dans les verres co-dopés 0,5Pr3+-10Yb3+ pour le processus de conversion d’un photon bleu en deux photons IRThe project joins in the development of miniaturized laser sources RGB for display and videoprojection, frequency conversion in solar cells.Fluoride glasses ZLAG ( ZrF4-LaF3-AlF3-GaF3) co-doped with rare earths were studied. This glass has a low phonon energy, a strong solubility of the rare earth ions and can be fabricated as thin films by PVD. It is also the precursor of transparent glass-ceramics. Similar emissions in both co-doped bulk and waveguides have been observed ; blue, orange, red emission for Pr3+-Yb3+ and blue, red emission for Tm3+-Yb3+. The RGB emission in bulk Tm3+-Er3+-Yb3+ tri-doped glass seems promising. Furthermore, the absorption cross section of Pr3+ and Yb3+ ions has been increased by 30% with the ceraming process.An energy transfer efficiency (ETE) of 92% has been obtained for co-doped glass with 0,5Pr3+-10Yb3+ for the conversion process of a blue photon into two infrared one
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Azzopardi, Alban. "Evolution microstructurale à haute température de barrières thermiques déposées par évaporation : influence sur la conductivité thermique et le module d'élasticité." Paris 6, 2003. http://www.theses.fr/2003PA066010.
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ANTUNES, RENATO A. "Caracterização do comportamento frente à corrosão de um aço inoxidável austenítico para aplicações biomédicas com revestimentos PVD de TiN, TiCN e DLC." reponame:Repositório Institucional do IPEN, 2006. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11493.
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Made available in DSpace on 2014-10-09T12:52:30Z (GMT). No. of bitstreams: 0Made available in DSpace on 2014-10-09T14:02:35Z (GMT). No. of bitstreams: 0
Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
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PERRIN, GERALDINE. "Elaboration par pvd et caracterisation de couches minces ferromagnetiques sur film souple pour des applications hyperfrequence." Université Joseph Fourier (Grenoble), 1996. http://www.theses.fr/1996GRE10199.
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Ce travail concerne l'elaboration et l'etude de nouveaux materiaux magnetiques destines a des applications radiofrequences et hyperfrequences entre 1 mhz et 20 ghz. Jusqu'a present, les materiaux preferes dans les applications radiofrequences et hyperfrequences ont ete les ferrites. Il s'agit de materiaux isolants mais ferrimagnetiques donc a faible aimantation spontanee. Or les alliages ferromagnetiques ont des proprietes bien superieures aux ferrites en particulier des aimantations 3 a 4 fois superieures. Mais ce sont des conducteurs metalliques qui ne peuvent etre utilises sous forme massive aux frequences elevees a cause de l'effet de peau. Le present travail transpose la solution du feuilletage aux hyperfrequences et demontre que des composites stratifies du type metal ferromagnetique - isolant peuvent concurrencer les ferrites et meme etre plus performants dans nombre de cas a condition de realiser des taux de charge convenables. Dans ce but, nos composites sont constitues d'empilements de films minces de polymere revetus du depot magnetique. Nous demontrons la possibilite de recouvrir par pulverisation magnetron au deroule de grandes surfaces de polymere (mylar ou kapton d'epaisseur 12 microns voire 3. 5 microns) par des alliages amorphes a base de cobalt, ayant en particulier une anisotropie uniaxiale planaire bien definie et controlee. Les proprietes dynamiques prevues (notamment la violation de la limite de snoek) sont verifiees et differentes solutions sont proposees pour modifier a volonte le spectre de permeabilite. Enfin, deux exemples de realisation de composants hyperfrequences utilisant ces materiaux sont donnes. Sur le plan theorique, nous corrigeons le modele classique de rytov et donnons les caracteristiques electromagnetiques effectives du composite. Nous calculons la contribution magneto-elastique a l'anisotropie dans le cas ou les contraintes sont anisotropes et la rigidite du substrat du meme ordre de grandeur que celle de la couche
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Mukherjee, Sriparna. "Evolution of microstructure and residual stress in disc-shape EB-PVD thermal barrier coatings and temperature profile of high pressure turbine blade." Master's thesis, University of Central Florida, 2011. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4989.
Full textAbstract:
A detailed understanding of failure mechanisms in thermal barrier coatings (TBCs) can help develop reliable and durable TBCs for advanced gas turbine engines. One of the characteristics of failure in electron beam physical vapor deposited (EB-PVD) TBCs is the development of instability, named rumpling, at the interface between (Ni, Pt)Al bond coat and thermally grown oxide (TGO). In this study, thermal cycling at 1100[degrees]C with 1 hr dwell time was carried out on 25.4mm disc specimens of TBCs that consisted of EB-PVD coated ZrO[sub2]-7wt.%Y[sub2]O[sub3], (Pt,Ni)Al bond coat, and CMSX-4 Ni-based superalloy. At specific fraction of lifetime, TBCs were examined by electron microscopy and photostimulated luminescence (PL). Changes in the average compressive residual stress of the TGO determined by PL and the magnitude of rumpling, determined by tortuosity from quantitative microstructural analyses, were examined with respect to the furnace thermal cyclic lifetime and microstructural evolution of TBCs. The combination of elastic strain energy within the TGO and interfacial energy at the interface between the TGO and the bond coat was defined as the TGO energy, and its variation with cyclic oxidation time was found to remain approximately constant ~135J/m[super2] during thermal cycling from 10% to 80% thermal cyclic lifetime. Parametric study at ~135J/m[super2] was performed and variation in residual stress with rumpling for different oxide scale thicknesses was examined. This study showed that the contribution of rumpling in residual stress relaxation decreased with an increase in TGO thickness. High pressure turbine blades serviced for 2843 hours and in the as coated form were also examined using electron microscopy and photostimulated luminescence. The difference in residual stress values obtained using PL on the suction and pressure sides of as-coated turbine blade were discussed.; The presence of a thick layer of deposit on the serviced blade gave signals from stress free alpha]-Al[sub2]O[sub3] in the deposit, not from the TGO. The TGO growth constant data from the disc-shape TBCs, thermally cycled at 1100??C, and studies by other authors at different temperatures but on similar EB-PVD coated TBCs with (Pt, Ni)Al bond coat and CMSX-4 Ni- based superalloy were used to determine the temperature profile at the YSZ/bond coat interface. The interfacial temperature profiles of the serviced blade and the YSZ thickness profile were compared to document the variable temperature exposure at the leading edge, trailing edge, suction and the pressure side.ID: 030423389; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Thesis (M.S.)--University of Central Florida, 2011.; Includes bibliographical references (p. 90-92).
M.S.
Masters
Mechanical, Materials, and Aerospace Engineering
Engineering and Computer Science
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Lorenz, Erik E. "Atomistische Modellierung und Simulation des Filmwachstums bei Gasphasenabscheidungen." Master's thesis, Universitätsbibliothek Chemnitz, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-159520.
Full textAbstract:
Gasphasenabscheidungen werden zur Produktion dünner Schichten in der Mikro- und Nanoelektronik benutzt, um eine präzise Kontrolle der Schichtdicke im Sub-Nanometer-Bereich zu erreichen. Elektronische Eigenschaften der Schichten werden dabei von strukturellen Eigenschaften determiniert, deren Bestimmung mit hohem experimentellem Aufwand verbunden ist.
Die vorliegende Arbeit erweitert ein hochparalleles Modell zur atomistischen Simulation des Wachstums und der Struktur von Dünnschichten, welches Molekulardynamik (MD) und Kinetic Monte Carlo-Methoden (KMC) kombiniert, um die Beschreibung beliebiger Gasphasenabscheidungen. KMC-Methoden erlauben dabei die effiziente Betrachtung der Größenordnung ganzer Nano-Bauelemente, während MD für atomistische Genauigkeit sorgt.
Erste Ergebnisse zeigen, dass das Parsivald genannte Modell Abscheidungen in Simulationsräumen mit einer Breite von 0.1 µm x 0.1 µm effizient berechnet, aber auch bis zu 1 µm x 1 µm große Räume mit 1 Milliarden Atomen beschreiben kann. Somit lassen sich innerhalb weniger Tage Schichtabscheidungen mit einer Dicke von 100 Å simulieren. Die kristallinen und amorphen Schichten zeigen glatte Oberflächen, wobei auch mehrlagige Systeme auf die jeweilige Lagenrauheit untersucht werden. Die Struktur der Schicht wird hauptsächlich durch die verwendeten molekulardynamischen Kraftfelder bestimmt, wie Untersuchungen der physikalischen Gasphasenabscheidung von Gold, Kupfer, Silizium und einem Kupfer-Nickel-Multilagensystem zeigen. Stark strukturierte Substrate führen hingegen zu Artefakten in Form von Nanoporen und Hohlräumen aufgrund der verwendeten KMC-Methode. Zur Simulation von chemischen Gasphasenabscheidungen werden die Precursor-Reaktionen von Silan mit Sauerstoff sowie die Hydroxylierung von alpha-Al2O3 mit Wasser mit reaktiven Kraftfeldern (ReaxFF) berechnet, allerdings ist weitere Arbeit notwendig, um komplette Abscheidungen auf diese Weise zu simulieren.
Mit Parsivald wird somit die Erweiterung einer Software präsentiert, die Gasphasenabscheidungen auf großen Substraten effizient simulieren kann, dabei aber auf passende molekulardynamische Kraftfelder angewiesen ist.
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Eroglu, Huseyin Cuneyt. "Design Of Reflective &." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/2/12611057/index.pdf.
Full textAbstract:
In order to improve the efficiency of various optical surfaces, optical coatings are used. Optical coating is a process of depositing a thin layer of a material on an optical component such as mirror or lens to change reflectance or transmittance.
There are two main types of coatings namelyreflective and antireflective (AR) Coatings. Reflective and antireflective coatings have long been developed for a variety of applications in all aspects of use
for optical and electro-optical systems in telecommunications, medicine, military products and space applications. In this thesis, the main properties of reflective and antireflective coatings, the thin film deposition techniques, suitable coating materials for space applications, space environment effects on coating materials and coating design examples which are developed using MATLAB for space applications will be discussed.
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Lorenz, Erik E. "Atomistische Modellierung und Simulation des Filmwachstums bei Gasphasenabscheidungen." Master's thesis, Fraunhofer ENAS, 2014. https://monarch.qucosa.de/id/qucosa%3A20181.
Full textAbstract:
Gasphasenabscheidungen werden zur Produktion dünner Schichten in der Mikro- und Nanoelektronik benutzt, um eine präzise Kontrolle der Schichtdicke im Sub-Nanometer-Bereich zu erreichen. Elektronische Eigenschaften der Schichten werden dabei von strukturellen Eigenschaften determiniert, deren Bestimmung mit hohem experimentellem Aufwand verbunden ist.
Die vorliegende Arbeit erweitert ein hochparalleles Modell zur atomistischen Simulation des Wachstums und der Struktur von Dünnschichten, welches Molekulardynamik (MD) und Kinetic Monte Carlo-Methoden (KMC) kombiniert, um die Beschreibung beliebiger Gasphasenabscheidungen. KMC-Methoden erlauben dabei die effiziente Betrachtung der Größenordnung ganzer Nano-Bauelemente, während MD für atomistische Genauigkeit sorgt.
Erste Ergebnisse zeigen, dass das Parsivald genannte Modell Abscheidungen in Simulationsräumen mit einer Breite von 0.1 µm x 0.1 µm effizient berechnet, aber auch bis zu 1 µm x 1 µm große Räume mit 1 Milliarden Atomen beschreiben kann. Somit lassen sich innerhalb weniger Tage Schichtabscheidungen mit einer Dicke von 100 Å simulieren. Die kristallinen und amorphen Schichten zeigen glatte Oberflächen, wobei auch mehrlagige Systeme auf die jeweilige Lagenrauheit untersucht werden. Die Struktur der Schicht wird hauptsächlich durch die verwendeten molekulardynamischen Kraftfelder bestimmt, wie Untersuchungen der physikalischen Gasphasenabscheidung von Gold, Kupfer, Silizium und einem Kupfer-Nickel-Multilagensystem zeigen. Stark strukturierte Substrate führen hingegen zu Artefakten in Form von Nanoporen und Hohlräumen aufgrund der verwendeten KMC-Methode. Zur Simulation von chemischen Gasphasenabscheidungen werden die Precursor-Reaktionen von Silan mit Sauerstoff sowie die Hydroxylierung von alpha-Al2O3 mit Wasser mit reaktiven Kraftfeldern (ReaxFF) berechnet, allerdings ist weitere Arbeit notwendig, um komplette Abscheidungen auf diese Weise zu simulieren.
Mit Parsivald wird somit die Erweiterung einer Software präsentiert, die Gasphasenabscheidungen auf großen Substraten effizient simulieren kann, dabei aber auf passende molekulardynamische Kraftfelder angewiesen ist.:Inhaltsverzeichnis
Abbildungsverzeichnis
Tabellenverzeichnis
Abkürzungsverzeichnis
Symbolverzeichnis
1 Einleitung
2 Grundlagen
2.1 Gasphasenabscheidungen
2.1.1 Physikalische Gasphasenabscheidung
2.1.2 Chemische Gasphasenabscheidung
2.1.3 Atomlagenabscheidung
2.1.4 Methoden zur Simulation von Gasphasenabscheidungen
2.2 Molekulardynamik
2.2.1 Formulierung der Molekulardynamik
2.2.2 Auswahl verfügbarer Molekulardynamik-Software
2.2.3 Molekulardynamische Kraftfelder
2.3 Kinetic Monte Carlo-Methoden
2.4 Datenstrukturen
2.4.1 Numerische Voraussetzungen an Gasphasenabscheidungen
2.4.2 Vergleich der Laufzeiten für verschiedene Datenstrukturen
2.4.3 Effiziente Datenstrukturen
2.4.4 Alpha-Form
3 Methoden und Modelle
3.1 Stand der Forschung
3.1.1 Anwendungen von KMC-Simulationen für die Gasphasenabscheidung
3.1.2 Anwendung von MD-Simulationen für die Gasphasenabscheidung
3.2 Parsivald-Modell
3.2.1 Zielsetzung für Parsivald
3.2.2 Beschreibung des Parsivald-Modells
3.2.3 Annahmen und Einschränkungen
3.2.4 Erweiterungen im Rahmen der Masterarbeit
3.2.5 Behandlung von fehlerhaften Ereignissen
3.3 Laufzeitanalyse von Parsivald-Simulationen
3.3.1 Ereignis-Laufzeit TE
3.3.2 Ereignis-Durchsatz RE
3.3.3 MD-Laufzeit TMD
3.3.4 Worker-Laufzeit Tworker
3.3.5 Serielle Laufzeit T1
3.3.6 Anzahl der parallelen Prozesse p
3.3.7 Workerdichte rhoworker
3.3.8 Parallele Laufzeit Tp
3.3.9 Speedup Sp
3.3.10 Parallele Effizienz Ep
3.3.11 Auswertung der Laufzeitparameter
3.3.12 Fazit
3.4 MD-Simulationen: Methoden und Auswertungen
3.4.1 Zeitskalen in MD-Simulationen
3.4.2 Relaxierungen
3.4.3 Strukturanalysen
3.4.4 Bestimmung der Dichte und Temperatur
3.4.5 Radiale Verteilungsfunktionen, Bindungslänge und Koordinationszahl
3.4.6 Oberfläche, Schichtdicke, Rauheit und Porösität
3.4.7 Reaktionen und Stabilität von Molekülen
4 Simulationen von Gasphasenabscheidungen
4.1 Gold-PVD
4.1.1 Voruntersuchungen
4.1.2 Thermodynamische Eigenschaften
4.1.3 Simulation von Gold-PVD
4.1.4 Skalierbarkeit mit der Simulationsgröße
4.1.5 Fazit
4.2 Kupfer-PVD
4.2.1 Voruntersuchungen
4.2.2 Thermodynamische Eigenschaften
4.2.3 Simulation von Kupfer-PVD
4.2.4 Untersuchung der maximalen Workerdichte
4.2.5 Fazit
4.3 Multilagen-PVD
4.3.1 Multilagen-Simulationen mit Parsivald
4.3.2 Vergleich mit Ergebnissen reiner MD-Simulationen
4.3.3 Vergleich der Parallelisierbarkeit
4.3.4 Fazit
4.4 Silizium-PVD
4.4.1 Voruntersuchungen
4.4.2 Simulationen von Silizium-PVD
4.4.3 Fazit
4.5 Aluminiumoxid-ALD
4.5.1 ReaxFF-Parametersätze
4.5.2 Voruntersuchungen
4.5.3 Fazit
5 Zusammenfassung und Ausblick
5.1 Zusammenfassung
5.2 Ausblick
A Physikalische Konstanten und Stoffeigenschaften
B Datenstrukturen
B.1 Übersicht über KMC-Operationen
B.2 Beschreibung grundlegender Datenstrukturen
B.3 Delaunay-Triangulationen
B.3.1 Ausgewählte Eigenschaften einer Delaunay-Triangulation
B.3.2 Algorithmen zur Konstruktion einer Delaunay-Triangulation
C Ergänzungen zur Laufzeitanalyse von Parsivald
C.1 Einfluss der Ereignis-Laufzeit auf die effiziente Raumgröße weff
C.2 Zusätzliche Einflüsse auf das Maximum der Prozesse pmax
C.3 Abschätzung der maximalen Workerdichte per Random Sequential Adsorption
D Ergänzungen zur Simulation von Gold-PVD
E Multilagen-PVD
E.1 Porenbildung bei Unterrelaxation
E.2 Simulationen mit Lagendicken von jeweils 5 nm
F Simulation der CVD-Precursormoleküle Silan und Sauerstoff
F.1 Stabilität der Precursormoleküle
F.2 Reaktion der Precursormoleküle
Literaturverzeichnis
32
Kramer, Andrea. "Growth and characterization of silicon and germanium nanowhiskers." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2009. http://dx.doi.org/10.18452/15920.
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Die vorliegende Dissertation befasst sich mit dem Wachstum und der Charakterisierung von Silizium- und Germanium-Nanodrähten. Diese Strukturen gelten als aussichtsreiche Komponenten für zukünftige Bauelemente. Für die Anwendung ist die genaue Kenntnis der Größe, der kristallographischen Orientierung und der Position der Nanodrähte erforderlich. Ziel dieser Arbeit war daher die Untersuchung von Si- und Ge-Nanodrähten im Hinblick auf ihre Größe, Orientierung und Position. Die Herstellung erfolgte durch Physikalische Gasphasenabscheidung (PVD) im Ultrahochvakuum nach dem Vapor-Liquid-Solid (VLS)-Verfahren, das auf dem Wachstum aus Lösungsmitteltröpfchen basiert. Die Größe der Nanodrähte konnte im Falle von Silizium auf Si(111) mit Gold als Lösungsmittel durch die Parameter des Experiments reproduzierbar bestimmt werden. Höhere Goldbedeckung und höhere Substrattemperaturen führten zu Tröpfchen mit größerem Duchmesser und somit zu dickeren Drähten. Längere Si-Verdampfungszeiten und höhere Si-Verdampfungsraten führten zu längeren Drähten. Dünnere Drähte wuchsen schneller als dickere. Als zweites Lösungsmittel wurde Indium untersucht, da es sich im Vergleich zu Gold nicht nachteilig auf die elektronischen Eigenschaften von Silizium auswirkt. Basierend auf den Ergebnissen zur Tröpfchenbildung konnten die besseren Wachstumsresultate mit Gold erklärt werden. Germanium-Nanodrähte, die aus Goldtröpfchen auf Ge(111) gezüchtet wurden, zeigten im Gegensatz zu den Si-Nanodrähten nicht die kristallographische [111]-Orientierung des Substrates, sondern eine -Orientierung, was durch Berechnungen von Keimbildungsenergien auf verschiedenen Kristallflächen erklärt werden konnte. Zur Anordnung von Metalltröpfchen und damit von Nanodrähten wurden Substrate mithilfe von fokussierten Ionenstrahlen (FIB) vorstrukturiert, um die Tröpfchenbildung an bestimmten Stellen zu begünstigen. Es gelang, aus angeordneten Goldtröpfchen epitaktisch gewachsene Si- und Ge-Nanodrähte zu züchten.This dissertation deals with the growth and the characterization of silicon and germanium nanowhiskers, also called nanorods or nanowires. The investigation of these structures is of great interest as they represent promising building blocks for future electronic devices. With regard to a possible application, the knowledge of size, crystallographic orientation and position of the nanowhiskers is essential. The purpose of this work was, therefore, to investigate the growth of Si and Ge nanowhiskers with regard to their size, orientation and position. The nanowhiskers were grown via physical vapor deposition (PVD) in ultra-high vacuum using the vapor-liquid-solid (VLS) mechanism which is based on growth from solution droplets. The size of the nanowhiskers could be reproducibly determined by the experimental parameters in the case of Si nanowhiskers on Si(111) with gold as the solvent. A higher gold coverage as well as a higher substrate temperature led to larger droplet diameters and thus to thicker whiskers. A longer silicon evaporation time and a higher silicon rate led to longer whiskers. Thinner whiskers grew faster than thicker ones. A second material used as the solvent was indium as it is more suitable for electronic application compared to gold. Based on results of droplet formation of the two solvents on silicon, the better results of whisker growth using gold could be explained. Ge nanowhiskers grown from gold droplets on Ge(111) did not show the [111] orientation of the substrate as in the case of Si nanowhiskers on Si(111) but a orientation. By calculating nucleation energies on different crystal facets, the experimental findings could be explained. To position nanodroplets of the solvent material and thus to obtain a regular arrangement of nanowhiskers, substrates were pre-structured with nanopores by focused ion beams (FIB). Silicon and germanium nanowhiskers could be epitaxially grown from ordered arrays of gold droplets.
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Júnior, Adonias Ribeiro Franco. "Obtenção de revestimentos dúplex por nitretação a plasma e PVD-TiN em aços ferramenta AISI D2 e AISI H13." Universidade de São Paulo, 2003. http://www.teses.usp.br/teses/disponiveis/3/3133/tde-02102003-114623/.
Full textAbstract:
No presente trabalho foi avaliado o efeito da microestrutura e da capacidade de suportar carregamento de camadas nitretadas produzidas em aços ferramenta AISI H13 e AISI D2 sobre a aderência e a resistência ao desgaste microabrasivo de revestimentos de TiN-PVD. Em cada um desses aços, foram produzidas camadas nitretadas de diferentes estruturas e espessuras, e foram determinadas experimentalmente as curvas potencial início de formação de camada branca, para a nitretação a 520oC. Para o aço ferramenta AISI H13, o emprego de tempos de pré-tratamento de nitretação mais prolongados ( aproximadamente 11 h) foi necessário para aprofundar a camada nitretada e, conseqüentemente, aumentar a capacidade de suportar carregamento dos revestimentos, evitando a formação de bordas que provocam o lascamento e a escamação das camadas de TiN. Observou-se que esse tipo de falha persiste se a zona de endurecimento for pouco profunda, uma vez que a transição de propriedades mecânicas da camada de TiN para o núcleo não nitretado continua abrupta e a capacidade de suportar carregamento da camada nitretada ainda é baixa. Por outro lado, curtos tempos de nitretação (aproximadamente 42 min.) foram suficientes para aumentar a aderência das camadas de TiN ao aço ferramenta D2, pois o núcleo não nitretado desse aço possui uma capacidade de suportar carregamento razoável. Observou-se que a resistência ao desgaste microabrasivo e a aderência dos revestimentos são prejudicadas com a presença de uma camada preta na interface camada de TiN/camada nitretada. Quando a superfície dos revestimentos é carregada, falhas do tipo casca de ovo facilmente ocorrem.In this work, the influence of both the microstructure and the load-bearing capacity of nitrided layers, formed on top of AISI D2 and AISI H13 tool steels, on adhesion and wear resistance of PVD-TiN coatings was studied. The threshold nitriding potential curves for the above mentioned steels and the optimum conditions of the pre-treatments which increased the adhesion as well as the wear resistance of the PVD-TiN were determined experimentally. By using longer nitriding times (about 11 h) and lower nitrogen contents in the gas mixture (about N2-5%vol.), it was possible to minimize the pile-up degree of the TiN/H13 nitrided substrates and, consequently, the occurrence of coatings chipping. This flaw persists when the nitrided layer is thin, due to an abrupt transition of mechanical properties at the TiN coating / steel core interface. Shorter nitriding times (about 42 min.) and lower nitrogen contents (about N2-5%vol.), on the other hand, are sufficient to guarantee a better adhesion of TiN coatings on AISI D2 tool steel, as the core of such steel possesses relatively better load-bearing capacity than the AISI H13 tool steel. The presence of a black layer at the TiN/nitrided layer interface was observed in all coatings deposited over nitrided layers produced above the threshold nitriding potential curves. This layer affects adversely the wear resistance and the adhesion of the TiN coatings. When higher loads are applied on the coated surface, egg shell type flaws easily occur.
34
Buxton, Robert Charles. "Direct simulation Monte Carlo modelling of physical vapour deposition." Thesis, University of Leeds, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.426851.
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Ahmed, W. "Studies in low pressure chemical vapour deposition of polycrystalline silicon." Thesis, University of Salford, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.376853.
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Knorr, Nicholas J. "Fundamental studies of growth mechanisms in physical vapour deposition of aluminium." Thesis, University of Salford, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.365971.
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Smith, James Anthony. "Laser diagnostics of a diamond depositing chemical vapour deposition gas-phase environment." Thesis, University of Bristol, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.247541.
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Yimamu, (Imam) Maiwulidan (Mewlude). "Chemical vapour deposition of boron-carbon thin films from organoboron precursors." Licentiate thesis, Linköpings universitet, Tunnfilmsfysik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-123909.
Full textAbstract:
Boron-carbon (BxC) thin films enriched in 10B are potential neutron converting layers for 10Bbased solid-state neutron detectors given the good neutron absorption cross-section of 10B atoms in the thin film. Chemical Vapour Deposition (CVD) of such films faces the challenge that the maximum temperature tolerated by the aluminium substrate is 660 °C and low temperature CVD routes for BxC films are thus needed. This thesis presents the use of two different organoboron precursors, triethylboron –B(C2H5)3 (TEB) and trimethylboron – B(CH3)3 (TMB) as single-source precursors for CVD of BxC thin films. The CVD behaviour of TEB in thermal CVD has been studied by both BxC thin film deposition and quantum chemical calculations of the gas phase chemistry at the corresponding CVD conditions. The calculations predict that the gas phase reactions are dominated by β-hydride eliminations of C2H4 to yield BH3. In addition, a complementary bimolecular reaction path based on H2-assisted C2H6 elimination to BH3 is also present at lower temperatures in the presence of hydrogen molecules. A temperature window of 600 – 1000 °C for deposition of X-ray amorphous BxC films with 2.5 ≤ x ≤ 4.5 is identified showing good film density (2.40 – 2.65 g/cm3) which is close to the bulk density of crystalline B4C, 2.52 g/cm3 and high hardness (29 – 39 GPa). The impurity level of H is lowered to < 1 at. % within the temperature window. Plasma chemical vapour deposition has been studied using TMB as single-source precursor in Ar plasma for investigating BxC thin film deposition at lower temperature than allowed by thermal CVD and further understanding of thin film deposition process. The effect of plasma power, total pressure, TMB and Ar gas flow on film composition and morphology are investigated. The highest B/C ratio of 1.9 is obtained at highest plasma power of 2400 W and TMB flow of 7 sccm. The H content in the films seems constant at 15±5 at. %. The B-C bond is dominant in the films with small amount of C-C and B-O bonds, which are likely due to the formation of amorphous carbon and surface oxidation, respectively. The film density is determined as 2.16±0.01 g/cm3 and the internal compressive stresses are measured to be <400 MPa.
39
Welters, Martin [Verfasser]. "Potenzial der High-Speed Physical Vapour Deposition Technologie zur Abscheidung oxidischer Werkzeugbeschichtungen / Martin Welters." Düren : Shaker, 2021. http://d-nb.info/1233547852/34.
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Yang, Shicai. "The structure and control of Ti2N phases produced by unbalanced magnetron sputtering." Thesis, Sheffield Hallam University, 1997. http://shura.shu.ac.uk/20583/.
Full textAbstract:
Physical vapour deposition (PVD) techniques used for the application of advanced surface engineering materials have been developed over many years, but only in about the last 10 years has the unbalanced magnetron sputtering (UBMS) PVD technique been developed and emerged as one of the most promising techniques for depositing reliable and high quality films used in industrial production. Hard coatings have been studied for many years for the purpose of improving the performance of various tools, mechanical parts, and engineering components. The most studied binary hard coatings (such as stoichiometric titanium nitrides and titanium carbides) and the ternary hard coating (such as titanium carbonitride) have been developed for wear resistance for many years. Although many investigations have been made into the production of coatings with stoichiometric phases, it is both scientifically and commercially interesting to investigate the production and reproducibility of the pure titanium sub-nitride Ti2N films. The first results in chapter 5 describe work carried out to investigate the effect of nitrogen and carbon concentration within the films and was a prelude to the main activity of the development of Ti2N films using commercial conditions. The work for Ti2N was carried out without substrate rotation in the UBMS coating process. The static deposition processes were studied to give a better understanding of the effect of partial pressures on the compositions of the Ti-N films. The phase development as a function of the composition of the films was investigated. The main contribution during this procedure was to achieve a suitable range of nitrogen partial pressure by which the films containing pure Ti2N phase were produced using a UBMS deposition technique. The nitrogen content of the film was very sensitive to variation in nitrogen partial pressure and the nitrogen concentration influenced the phases developed in the films. The reproducibility of the pure Ti2N phase was also discussed in this initial work. A series of extensive experiments were conducted to investigate the formation of Ti2N phase in the UBMS deposition processes using one to three fold rotations. The nitrogen partial pressure of the deposition process was basically determined from the results of the initial work. The effect of substrate rotation on the film composition during processing was studied. In general the film deposited using substrate rotation consisted of different composition using the same chamber condition in one process in which the nitrogen content of the coating increased from one fold rotation to three fold rotation. The film containing dominant eTi2N phase could be produced on a sample using three fold rotation in a process whilst the multiphase compositions (aTiN0.3 + eTi2N) were developed on the sample using the one and two fold rotations in the same process. Characteristics of the eTi2N films and the films containing multiphase compositions were investigated using transmission electron microscopy (TEM), scanning electron microscopy (SEM), glow discharge optical emission spectrometer (GDOES), X-ray diffraction (XRD), and a variety of mechanical testing instruments. The eTi2N films have very smooth surface, very dense and fine columnar structure, relatively high hardness, and excellent adhesion with the substrate. The drilling tests using coated high speed steel drills compared the coatings containing eTi2N phase with those containing a single TiN phase and showed excellent wear resistant results.6.
41
McBride, Gillian M. "Physical and optical characterisation of carbon-silicon layers produced by rapid thermal chemical vapour deposition." Thesis, Queen's University Belfast, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.286865.
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Lawal, Josephine. "Physical vapour deposition of aluminium-rich nanostructured/amorphous metallic coatings for wear and corrosion protection." Thesis, University of Sheffield, 2017. http://etheses.whiterose.ac.uk/18364/.
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This research is aimed at designing and depositing multi-functional aluminium-based Physical Vapour Deposition (PVD) coatings that can serve as a protection for light alloys, non-ferrous alloys and low alloy steels against wear and corrosion. Coatings deposition was achieved by exploring the capabilities an environmentally-friendly plasma-assisted PVD process (i.e. closed-field unbalanced magnetron sputtering method). Three deposition sequences (series 1, 2 and 3) were undertaken, using two different target configurations, in an argon or argon/nitrogen atmosphere. A wide range of coatings compositions was deposited on commonly used engineering alloy substrates (i.e. austenitic stainless steel, AISI 304; low alloy steel, AISI 4145 and high speed steel, AISI M2), as well as silicon wafer. A variety of coatings characterisations were carried out; these include: Scanning and Transmission Electron Microscopy (SEM/TEM), Focussed Ion Beam microscopy (FIB), optical microscopy, X-Ray Diffraction (XRD), Energy-Dispersive X-ray analysis (EDX) and Glow Discharge Optical Emission Spectrometry (GDOES). The International Centre for Diffraction Data (ICDD) PDF-4+/SIeve+ phase identification database and digital pattern simulation tool was demonstrated to be useful for phase identification and was also extended to crystallite size estimation. Nanoindentation and micro-hole drilling tests were carried out to assess coating mechanical properties. Coating tribological properties were evaluated by reciprocating-sliding and slurry micro-abrasion wear tests. The responses (in terms of open circuit potential (OCP) and potentiodynamic polarisation behaviour) of coatings to a neutral salt corrosive environment were also recorded. In addition, annealing was used to establish coatings thermal stability, as well as the possibility of producing nanostructured coatings by promoting devitrification in completely amorphous coatings (as deposited). A mathematical approach for analysing experimental results and predicting coating properties has also been proposed. Lightly-stressed, partially nanocrystalline and completely amorphous coatings (with a wide range of chemical compositions) were deposited. The thickness of coatings in the main deposition sequence (series 2) ranged from approximately 7 to 14 μm. Coatings showed relatively high hardness (ranging from 8 to 17 GPa) and low modulus (< 200 GPa) – matching closely the modulus of commonly used steel substrates (e.g. stainless steel). Excellent tribological properties, especially in terms of resistance to abrasion (comparable to those of common PVD ceramic coatings like CrN) were achieved. Coatings also possessed a wide range of corrosion properties, with OCP values between -0.3 and -0.6 V. Most of the coatings remained thermodynamically stable up to 600ᵒC. Results of various correlation analyses (and structural similarities of corresponding coatings in different deposition sequences) illustrate the reproducibility of the AlNiTiSiB(N) coatings deposited. The AlNiTiSiB(N) coatings presented in this Thesis are environmentally-benign and can be used in many engineering applications especially where there are concerns about simultaneous wear and corrosion attacks of the underlying metal substrate. The coatings can also be utilised for oxidation resistance in moderately high-temperature applications.
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Watson, Ian Michael. "Chemical vapour deposition of thin films using group 6 metal carbonyls and their monophosphane derivatives as precursors." Thesis, University of Kent, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329057.
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Murugavel, P. "Thin Films And Sub-Micron Powders Of Complex Metal Oxides Prepared By Nebulized Spray Pyrolysis And Brillouin Scattering Investigations Of Phase Transitions In Solids." Thesis, Indian Institute of Science, 2000. http://hdl.handle.net/2005/217.
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The thesis consists of two parts. Part 1 deals with the preparation of thin films and sub-micron powders of complex metal oxides by nebulized spray pyrolysis (NSP) and Part 2 consists of Brillouin scattering studies of solid materials exhibiting interesting phase transitions.
The simple technique of NSP has been employed to prepare thin films of A12O3, PbTiO3, Pb(Zr0.5Ti0.5)O3 (PZT) and PbZrO3 on single crystal substrate. The films were characterized by various techniques for their composition, structure, morphology and dielectric properties. Ferroelectric (FE) films of the configuration FE/LaNiO3/SiO2/Si (FE = PbTiO3 and PZT), wherein the LaNiO3 barrier electrode was also deposited on the SiO2/Si substrate by NSP, have been investigated. The films exhibit satisfactory ferroelectric properties. PbZrO3 films deposited on LaNiO3/SiO2/Si substrates show good features, including a reversible AFE ↔ FE transition. Sub-micron particles of TiO2, ZrO2, Pb(Zr0.5Ti0.5)O3, Al2O3, S1O2 and mullite have been prepared by NSP and characterized by various techniques.
Brillouin scattering has been used, for the first time, not only to characterize the Peierls transition but also the incommensurate to commensurate transition in the one-dimensional blue bronze, K0.3M0O3. The charge density wave transition in NbSe2 has also been investigated by Brillouin scattering. The charge ordering and antiferromag-netic transitions in single crystals of the rare earth manganates, Nd0.5Ca0.5MnO3 and Pr0.63Ca 0.37MnO3, have been investigated by Brillouin scattering. It is noteworthy that the temperature variation of the Brillouin shift and intensity parallel to that of the magnetization, thereby throwing light on magnetic excitations in charge-ordered state. Brillouin scattering investigations of C60 and C70 films have yielded values of the elastic moduli.
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Hon, Sherman Siu-Man. "Calcium vapour deposition on semiconducting polymers studied by adsorption calorimetry and visible light absorption." Thesis, University of British Columbia, 2007. http://hdl.handle.net/2429/863.
Full textAbstract:
A novel UHV microcalorimeter has been used to study the interaction between
calcium and three polymers: MEH-PPV, MEH-PPP and P3HT. All three polymers
behave differently in their reaction kinetics with calcium. On MEH-PPV we measure
45 μJ/cm² of heat generated in excess of the heat of bulk metal growth, 120 μJ/cm²
for MEH-PPP, and 100 μJ/cm² for P3HT. Comparison of the MEH-PPV and MEHPPP
data indicate that the initial reaction of calcium with MEH-PPV occurs at the
vinylene group. We propose, based on hypothetical models, that calcium reacts with
the vinylene groups of MEH-PPV with a reaction heat of 360 kJ/mol and at a
projected surface density of 1.7 sites/nm², while it reacts with the phenylene groups
of MEH-PPP in a two-step process with reaction heats of 200 and 360 kJ/mol
respectively, at a projected surface density of 3.5 sites/nm².
Optical absorption experiments, using either a 1.85 eV diode laser or a xenon lamp
coupled to a scanning monochromator, have also been performed using the same
calorimeter sensor. In the case of MEH-PPV, using the laser we find an optical
absorption cross-section of 3E-¹⁷ cm² per incident calcium atom at low coverages.
The change in absorptance at higher coverages correlates perfectly with the
population of reacted Ca atoms determined calorimetrically. The size of the
absorbance cross-section, and its position just within the band gap of the polymer, are
consistent with the reaction being one of polaron formation. Calcium does not appear
to dope P3HT, while the photon energy range of 1.5 to 3.75 eV used in these
experiments is likely too small for probing polaronic energy states in MEH-PPP.
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Chioncel, Mariana F. "Cobalt thin films produced by conventional and photo-assisted metal-organic chemical vapour deposition." Thesis, Keele University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.327638.
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Hellwig, Thomas. "Physical, electrochemical and mechanical characterisation of amorphous boron phosphide coatings prepared by plasma enhanced chemical vapour deposition (PECVD)." Thesis, University of the West of Scotland, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.545797.
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Whilst substantial empirical experimental investigation is available in the literature on amorphous Boron phosphide (BP) coatings, there is not much information about the scienti¯c properties exhibited by this material in var- ious applications such as in infra-red imaging systems. Also a great deal of the industrial application of amorphous BP coatings is in the area of infra- red imaging systems. This thesis is based on an attempt to understand the underpinning scienti¯c basis for the properties of amorphous Boron phos- phide coatings, using a range of surface, chemical, physical, electrochemical, computational (quantum mechanics) and mechanical characterisation tools. The results of this investigation has not only helped in unveiling the scien- ti¯c basis of some of the current empirically derived properties of amorphous BP coatings, used in the infra-red imaging industry, but has con¯rmed that amorphous BP is a potential coating for engineering substrates used in var- ious industries if the PECVD deposition process is optimised. This inves- tigation also establishes the link between the properties of amorphous BP coatings and the bonds in the different stoichiometric composition of the coatings.
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Bansen, Roman. "Solution growth of polycrystalline silicon on glass using tin and indium as solvents." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät, 2016. http://dx.doi.org/10.18452/17557.
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Mit der vorliegenden Arbeit wird das Wachstum von polykristallinem Silicium auf Glas bei niedrigen Temperaturen aus metallischen Lösungen in einem Zweistufenprozess untersucht. Im ersten Prozessschritt werden nanokristalline Siliziumschichten (nc-Si) hergestellt, entweder durch die direkte Abscheidung auf geheizten Substraten oder durch als ''Amorphous-Liquid-Crystalline''(ALC)-Umwandlung bezeichnete metall-induzierte Kristallisation. Im zweiten Prozessschritt dienen die Saatschichten als Vorlage für das Wachstum von deutlich größeren Kristalliten durch stationäre Lösungszüchtung. Die ALC-Prozessdauer konnte durch umfassende Parameterstudien signifikant reduziert werden. Die Charakterisierung der durch direkte Abscheidung auf geheizten Substraten entstehenden nc-Si Saatschichten offenbarte, dass es sich dabei um individuelle Saatkörner handelt, die in eine quasi-amorphe Matrix eingebettet sind. Die Oxidation der Saatschichten vor dem zweiten Prozessschritt wurde als ein wesentliches Hindernis für das Wachstum identifiziert. Als erfolgreichste Lösung zur Überwindung dieses Problems hat sich ein anfänglicher Rücklöseschritt erwiesen. Da diese Methode jedoch schwierig zu kontrollieren ist, wurde ein UV-Laser-System entwickelt und installiert. Erste Resultate zeigen epitaktisches Wachstum an den Stellen, an denen das Oxid entfernt wurde. Bei der Lösungszüchtung auf ALC-Schichten beginnt das Wachstum an einigen größeren Saatkristallen, von wo aus umliegende Gebiete lateral überwachsen werden. Obwohl Kristallitgrößen bis zu 50 Mikrometern erreicht wurden, war es noch nicht möglich, geschlossene Schichten zu erzielen. Durch Lösungszüchtung auf nc-Si Saatschichten hingegen konnte dieses Ziel erreicht werden. Geschlossene, polykristalline Si-Schichten wurden erzeugt, auf denen alle Si-Kristallite miteinander verbunden sind. Neben den Wachstumsexperimenten wurden 3D-Simulationen durchgeführt, in denen u.a. unterschiedliche Heizerkonfigurationen simuliert wurden.The subject of this thesis is the investigation of the growth of polycrystalline silicon on glass at low temperatures from metallic solutions in a two-step growth process. In the first process step, nanocrystalline Si (nc-Si) films are formed either by direct deposition on heated substrates, or by a metal-induced crystallization process, referred to as amorphous-liquid-crystalline (ALC) transition. In the second process step, these seed layers serve as templates for the growth of significantly larger Si crystallites by means of steady-state solution growth. Extensive parameter studies for the ALC process helped to bring down the process duration significantly. Characterization of the nc-Si seed layers, formed by direct deposition on heated substrates, showed that the layer is composed of individual seeds, embedded in a quasi-amorphous matrix. The oxidation of the seed layers prior to the second process step was found to be a major obstacle. The most successful solution has been an initial melt-back step. As the process is hard to control, though, a UV laser system has been developed and installed. First promising results show unobstructed epitaxial growth where the oxide has been removed. Steady-state solution growth on ALC seed layers was found to start from a few larger seed crystals, and then cover the surrounding areas by lateral overgrowth. Although crystallites with sizes of up to 50 micrometers were obtained, it was not yet possible to achieve full surface coverage with a continuous layer. By solution growth on nc-Si seed layers, however, it was eventually possible to achieve this goal. Continuous, polycrystalline Si layers were grown, on which all Si crystallites are interlocked. The growth experiments were accompanied by 3D simulations, in which e.g. different heater configurations have been simulated.
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Mukati, Kapil. "An alternative structure for next generation regulatory controllers and scale-up of copper(indium gallium)selenide thin film co-evaporative physical vapor deposition process." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 311 p, 2007. http://proquest.umi.com/pqdweb?did=1397912441&sid=12&Fmt=2&clientId=8331&RQT=309&VName=PQD.
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Thesis (Ph.D.)--University of Delaware, 2007.Principal faculty advisor: Babatunde Ogunnaike, Dept. of Chemical Engineering, and Robert W. Birkmire, Dept. of Materials Science & Engineering. Includes bibliographical references.
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Edström, Curt. "Wet etching of optical thin films." Thesis, Tekniska Högskolan, Högskolan i Jönköping, JTH, Kemiteknik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-13988.
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Evaluation of the wet etching properties of several different thin film oxidesgrown by physical vapour deposition was performed in this work. MgO, Al2O3,SiO2, TiO2, HfO2 ZrO2 and Y2O3 were coated on two types of substrates; Si andborosilicate glass and etching tests were performed in different etchingsolutions. MgF2 thin films have also been evaluated. Important aspects of the choice of the thin films was taken into account in orderto match to good optical properties such as refractive index (n), extinction coefficient (k) and optical thickness (TP) as well as good chemical properties in the wet etching process. A description is made of the physics of optical filters and how a combination of different oxides stacked onto each other can create interference filters. A description of the manufacturing process of the thin films where physical vapour deposition (PVD) was used is presented. Thermal shift of the optical spectra caused by porous coatings was investigated and analyses of the thin films by ellipsometry, surface profilometry and transmission spectrophotometry have been performed. The wet etching properties were evaluated by monitoring the transmission insituon transparent borosilicate glass substrates. A method of how to measure the wet etching rate for different thin films is described. A computer software was used to calculate the Pourbaix diagrams in order to understand the chemical behaviour of the etching solutions. The pH can have a significant impact on the etching behaviour. In case of TiO2, it can be dissolved in an alkaline solution of H2O2. The catalytically process behind this is evaluated. Etching rate for both Y2O3 andSiO2 were matched by adjusting the etchant concentration as a case example. The group IVB oxides are difficult to etch. The catalytic etching of TiO2 with peroxide is slow but detectable. Al2O3, Y2O3 and MgO are reasonably easy to etch but have too low refractive indices to be useful in multilayer optical filters. The In-situ etching instrument was found to be very useful for measuring etching rates.Utvärdering av våtkemiska egenskaper för flera olika oxidtunnfilmer utfördes idetta arbete på tunnfilmer av MgO, Al2O3, SiO2, TiO2, HfO2 ZrO2 and Y2O3 vakuumdeponerade på både kiselwafers och borosilikatglas. Etstester gjordes med ett flertal etslösningar. Även MgF2-tunnfilmer utvärderades. Både optiska och kemiska egenskaper togs i beaktande vid utvärderingen av tunnfilmerna. De optiska lagar som gäller för tunnfilmer redovisas, bl a hur kombinationer av olika oxider kan skapa interferrensfilter. En beskrivning av tillverkningsprocessen varvid PVD användes presenteras. Termiskt skift av det optiska transmissionsspektrat orsakat av porositet undersöktes. Analyser av tunnfilmerna med ellipsometri, profilometri och transmissions spektroskopi utfördes. Våtetsningsegenskaperna utvärderades genom att mäta in-situ vid etsprocessen på transparenta borosilikatglassubstrat. Metoden för att mäta etshastigheten för olika oxider är beskriven. Datorberäkningar av pourbaixdiagram användes för att skapa en förståelse av de kemiska egenskaperna för etslösningarna. Etsegenskaperna påverkas till stordel av lösningens pH. TiO2 kan etsas i basisk lösning av peroxid. Denna process utvärderades, likaså utvärderades etshasigheten för Y2O3 och SiO2 för att erhålla matchande par avoxider som en fallstudie. Grupp IVB oxiderna är mycket svåra att etsa. Katalytisk etsning av TiO2 med peroxid är detekterbar men långsam. Al2O3, Y2O3 och MgO är förhållandevis enkla att etsa men har för låga brytningsindex för att var praktiskt använbara i optiska multilagerfilter. In-situ etsinstrumentet befanns vara ett utmärkt verktyg för att mäta etshastigheten för tunnfilmer.