The majority of the structural weight of many common commercial aircrafts is composed of high strength aluminum alloys. The properties of high performance aluminum alloys such as a high strength to weight ratio (specific strength), ease of recycling, crash energy absorption capacity, and corrosion resistance make them ideal for use in the aerospace field. As a result of the high performance nature of the parts and specific properties of the materials, manufacturing requires intricate casting, precision machining, and specific heat treatments – which results in expensive components. As a result of its excellent corrosion resistance properties, pure aluminum coatings are commonly used in the aerospace field for corrosion protection of steel, aluminum alloy components, and titanium alloy components. The common method to deposit these coatings is called ion vapour deposition (IVD). These IVD aluminum coatings provide the coating adhesion, coverage, thickness, and corrosion resistance required to protect the part. The present study was motivated by the potential use of the cold gas dynamic spray (CGDS) process to repair a) damaged aluminum alloy aerospace parts and b) damaged pure aluminum IVD coatings. The primary research objective was to successfully produce these repairs using commercially available aluminum alloy feedstock powders deposited with commercially available CGDS equipment. This work was treated as prequalification work for The Boeing Company to commercialize this process and therefore the repairs aim to meet the same standards (military and industrial) required of the original aluminum alloy parts and IVD aluminum coatings. The use of CGDS was shown in this research to be a very promising as a process for the restoration of aluminum alloy aerospace components. The adhesion strength of the repaired aluminum components was found to be well above the accepted range for thermally sprayed repairs according to industrial standards. The repairs were subjected to a highly corrosive environment and showed only minor pitting. These sites could be reduced in the future with improved machining techniques and attention to surface detail prior to exposure to the salt fog. The only requirement that the repaired components did not meet was for the wear properties of the anodized layer, measured thought Taber abrasion testing. The results of this test, at times, approached the desired values, and it is believed that, in the future, the quality and consistency of the coatings could be improved and the test would meet industrial standards. The results of this research show that the use of CGDS as a process for the restoration of damaged aluminum IVD coatings is possible and is a promising alternative to conventional methods. The CGDS coatings were scrutinized to the same level as required of IVD coatings when they replaced toxic cadmium coatings in the late 1980s. The coating adhesion, demonstrated through glass bead abrasion and strip rupture testing, was shown to meet the current industrial standards. The corrosion testing of the repairs resulted in no visible red rust of the steel components, even when the steel was exposed.

La réparation des composants en alliages légers est un processus clés dans le domaine de l’aéronautique. Ces alliages sont abondamment utilisés dans les constructions aéronautiques notamment pour des composants à forte valeur ajoutée. Leur utilisation combinée à une optimisation de la conception des pièces permet de disposer de produits satisfaisants aux exigences de masse, de coût et de performances. Cependant l’utilisation de ces pièces est limitée dans le temps car divers endommagements peuvent survenir aussi bien lors de leurs manipulations que lors de leurs utilisations en service. Des solutions de retouches existent mais ne permettent pas toujours de redonner leur intégrité aux zones affectées. Ces limitations sont à l’origine d’un fort taux de rebut parmi les pièces à forte valeur ajoutée.Les multiples avantages du procédé Cold Spray en font un candidat idéal pour la projection de revêtements adaptés aux composants en alliages légers mis en oeuvre en aéronautique, que ce soit dans une logique de protection, de retouche ou de réparation. Il s’agit de reconstruire la pièce par un revêtement aux caractéristiques les plus proches possibles de celles du matériau de base. Ce travail de thèse consiste à optimiser l’ensemble des paramètres du procédé de projection dynamique à froid (Cold Spray) pour plusieurs couples substrat-revêtement combinant différents alliages d'aluminium, de magnésium et des composites à matrice métallique à base aluminium.La première étape a consisté à optimiser les paramètres principaux du procédé Cold Spray afin de s’affranchir du phénomène de colmatage pouvant intervenir au sein de la section divergente de la buse de projection. Ce phénomène a pour effet de diminuer la vitesse des particules, les revêtements obtenus devenant alors assez poreux. Une étude s’est ensuite focalisée sur l’optimisation de l’adhérence des couples substrats-revêtements. Il a été démontré le rôle primordial de la préparation de surface dans l’adhérence des revêtements où l’ancrage mécanique apparaît prépondérant. Enfin, une étude originale a été conduite pour mettre au point une méthodologie pour recharger localement une zone défectueuse sans avoir à recouvrir toute la surface du substrat. Une programmation hors ligne du robot a été employée afin de recouvrir deux types de défaut pré-usinés sur des blocs d’alliage d'aluminium. Les résultats sont satisfaisants avec des gains en temps de projection et des dépôts sans défaut après usinage. / The repair of light alloy parts is a major issue in aeronautics. Aluminum alloy and magnesium alloy are widely used in aircraft parts, especially for high value-added components. Their use combined to optimizing design allows to have satisfactory products meeting mass, cost and performance requirements. However, like any other life-limited components, various damages can occur not only during handling procedure but also while operating. Rectification solutions exist but do not always comply with requirements. These limitations entail high scrap rates among high value-added parts.The various advantages of the cold spray process make it an ideal candidate for suitable coatings for light alloy aircraft components as protective, retouching or repair methods. The aim is to rebuild the damaged part by a coating whose characteristics are closest to those of primary materials. This thesis proposes to optimize different cold spray parameters for several substrate-coating pairs combining different aluminum alloys, magnesium alloys and aluminum alloy-based metal matrix composites.The first step was to optimize the main parameters of cold spray process to prevent clogging phenomenon that may occur in the expansion part of the nozzle. It decreases particle kinetics and promotes porous coating. Then, adhesion optimization of substrate-coating couples was investigated. The substrate surface preparation is a key factor on coating adhesion, where the mechanical anchoring appears essential. Finally, an innovative study was conducted to develop a method to cover locally surface defects. Offline programming trajectories were used to fill up two kinds of pre-machined defaults on aluminum alloy blocks. Results are in good agreement with spray time savings and defect free coatings after machining.

<p>As a part of a more extensive project of developing a new finishing line at the Bolivian door manufacturer Tecno Carpinteria San Pedro this thesis presents the development process for a special designed spray booth. The thesis covers every phase from a product idea to a final concept design.</p><p>Working with finishing of furniture and other wooden products can effect the workers health in a negative way and damage the environment. The final result of the manufactured door is also depending on the how well the ventilation system in the working area is. Because of these reasons it is important to use safety equipment and a good ventilation system in the working area. As a part of this new finishing line San Pedro is in need of a special designed spray booth to control the spread of paint particles and other hazard substances that is a result of the finishing process.</p><p>Together with the consultant firm CADEFOR a spray booth is designed and a proposal design is presented in this thesis. The result is a design built up with a dry filter solution together with an extractor that creates a cross draft airflow towards the rear part of the spray booth. The result of the project together with some recommendations of increasing the capacity in the finishing line are also presented.</p>

Nanocomposite thin films with gold nanoparticles embedded in a host metal oxide prepared by spray pyrolysis deposition have been investigated. A single-step process has been developed using a one-pot solution containing precursors for both gold nanoparticles and host metal oxides. The films obtained display combined features of colouration, electrical conductivity and solar control. In this study two precursors for gold nanoparticles were used: preformed gold colloids and HAuCl₄. Three metal oxide host materials, TiO₂, SnO₂ and ZnO, were investigated. These films were deposited at a substrate temperature of 200-600 &deg;C. Powder X-ray diffraction analysis reveals the presence of metallic gold. SEM inspection typically showed particulate gold of 5-20 nm in diameter, distributed at the surface or within the host matrix. Optical spectroscopy showed an intense absorption in the visible region due to the characteristic surface plasmon resonance (SPR) effects of gold nanoparticles. The wavelength of the SPR peaks varies depending on the refractive index of surrounding host material which is significantly influenced by the substrate deposition temperature. On the other hand, SnO₂ and ZnO, together with the introduction of dopants, were further investigated as suitable materials for transparent conducting oxides (TCO). SnO₂:F films were found to attain very low electrical resistivity, while ZnO films exhibit higher transparency in the visible. A double layered structure with a TCO layer of SnO₂:F on top of a layer embedded with gold nanoparticles has been employed to achieve the combined functionalities of conductivity and colouration. The electrical conductivity is significantly enhanced compared to a nanocomposite single layer film due to the introduction of the TCO top layer. In this thesis, spray pyrolysis deposition has demonstrated a simple and rapid approach to the production of a variety of thin films. It can be immediately integrated with current industrial coating equipment and scaled up for large-scale production process.

As a part of a more extensive project of developing a new finishing line at the Bolivian door manufacturer Tecno Carpinteria San Pedro this thesis presents the development process for a special designed spray booth. The thesis covers every phase from a product idea to a final concept design. Working with finishing of furniture and other wooden products can effect the workers health in a negative way and damage the environment. The final result of the manufactured door is also depending on the how well the ventilation system in the working area is. Because of these reasons it is important to use safety equipment and a good ventilation system in the working area. As a part of this new finishing line San Pedro is in need of a special designed spray booth to control the spread of paint particles and other hazard substances that is a result of the finishing process. Together with the consultant firm CADEFOR a spray booth is designed and a proposal design is presented in this thesis. The result is a design built up with a dry filter solution together with an extractor that creates a cross draft airflow towards the rear part of the spray booth. The result of the project together with some recommendations of increasing the capacity in the finishing line are also presented.

In this study an experimental spray-rolling set-up is designed in order to produce rapidly solidified Al-Fe-V-Si flat product. Al-Fe-V-Si alloys produced by rapid solidification powder metallurgy (RSP/M) methods are mostly used in high temperature applications in aerospace and automotive industries. The RSP/M technique used is spray deposition, which is desirable because of the high cooling rates achieved, as a result fine silicide dispersoids and intermetallics are observed in the microstructure which are known to contribute to the mechanical properties i.e. high strength at elevated temperatures, thermal stability, fracture toughness, corrosion resistance. Since spray deposition is a droplet consolidation process a considerable amount of porosity is expected in the final product. In this work, spray rolling process, which consists of spray deposition and subsequent hot twin-rolling stage, is designed and developed by interpreting the results obtained from SEM, XRD, tensile, three point bending and hardness tests of the specimens formed in several design stages. Two original intermetallic phases characterized in this study are V3Si and V2Mg3Al18 .

Submitted by Denis Expedito Martins (denisexpeditomartins@yahoo.com.br) on 2018-01-22T12:35:28Z No. of bitstreams: 1 dissertação final DENIS.pdf: 2001070 bytes, checksum: 1015da2c8a0b759457a6f0471f26be1c (MD5) / Rejected by Ana Paula Santulo Custódio de Medeiros null (asantulo@rc.unesp.br), reason: Falta a capa no arquivo pdf. Deve ser utilizada aquela entregue pela Seção Técnica de Pós-Graduação no dia da Defesa. on 2018-01-22T16:51:24Z (GMT) / Submitted by Denis Expedito Martins (denisexpeditomartins@yahoo.com.br) on 2018-01-22T21:19:14Z No. of bitstreams: 1 dissertação final DENIS.pdf: 2353770 bytes, checksum: 2b86a8520d49b45d153eb873f0403561 (MD5) / Approved for entry into archive by Ana Paula Santulo Custódio de Medeiros null (asantulo@rc.unesp.br) on 2018-01-23T13:02:52Z (GMT) No. of bitstreams: 1 martins_de_me_rcla.pdf: 2264546 bytes, checksum: c6a41db1fcf4e53fca66f918fed76ebf (MD5) / Made available in DSpace on 2018-01-23T13:02:52Z (GMT). No. of bitstreams: 1 martins_de_me_rcla.pdf: 2264546 bytes, checksum: c6a41db1fcf4e53fca66f918fed76ebf (MD5) Previous issue date: 2018-01-04 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Este trabalho apresenta o estudo das propriedades elétricas de filmes finos de óxidos condutores transparentes (TCOs) obtidos por spray-pirólise. A fabricação de filmes finos de TCOs depositados por sputtering ou laser pulsado (PLD) é atraente para aplicações optoeletrônicas devido à alta condutividade elétrica e transmitância na faixa do visível, porém a dificuldade em cobrir grandes áreas é um fator limitante para o aumento da escala de produção. Por outro lado, a utilização de soluções de precursores orgânicos permite o uso de métodos de deposição relativamente simples (por exemplo, spin coating, spray, roll-to-roll, dentre outros) que permitem a cobertura de áreas extremamente grandes. Particularmente, o processo de spray-pirólise é um método de deposição simples, versátil, eficiente e de baixo custo que tem vários parâmetros de fabricação que podem ser variados para alcançar um desempenho ótimo do dispositivo. Desenvolvemos um sistema de deposição de spray-pirólise totalmente automatizado utilizando soluções aquosas de precursores de TCOs para obter filmes homogêneos, que foram avaliados para aplicação em dispositivos semicondutores através do desempenho elétrico quantificado pela técnica de caracterização elétrica d.c. corrente-tensão (I-V). Para determinar os melhores parâmetros de fabricação, variou-se a temperatura dos substratos (vidro de borosilicato) durante a deposição de 250 ºC a 400 ºC, o número de camadas depositadas (1 a 5), o tempo de deposição (de 5 a 150 s), diferentes pressões do ar comprimido utilizado no aerógrafo (0,7 a 2 bar), a concentração da solução (de 0,5 % a 3 % em massa) e a razão molar Al:Zn (de 5 % a 30 %), para os filmes de AZO. Utilizaram-se eletrodos de alumínio evaporados a vácuo com diferentes razões de aspecto (1/18, 2/9, 5/13, 5/9 e 8/9) para determinar a resistência de folha sobre toda a área do filme. Para determinar a condutividade elétrica dos filmes foi necessário fazer análise de microscopia de forca atômica (AFM) para descobrir a espessura dos filmes. A análise termogravimétrica (TGA) e a análise por infravermelha (FTIR) foram também utilizadas para verificar a formação da fase de óxido metálico dos compostos e a análise de difração de raio-X (XRD) foi utilizada para identificar qual a estrutura formada nos filmes / This work presents the study of the electrical properties of thin films of transparent conductors oxides (TCOs) obtained by spray-pyrolysis deposition. The fabrication of thin films of TCOs by RF sputtering or pulsed-laser deposition (PLD) is attractive for optoelectronic applications due the high electric conductivity and transmittance in the visible spectrum range. However the difficulty to cover extra-large areas is a limiting factor for upscaling production. On the other hand, the use of organic precursor solutions allow the use of relatively simple deposition methods (e.g. spin-coating, spray, roll-to-roll) that enable the coverage of very large areas. Particularly, spray-pyrolysis is a simple, versatile, efficient and of low cost deposition method wich has several manufacturing parameters that can be varied to achieve optimal device performance. We developed a fully automated spray-pyrolysis deposition system using aqueous solutions of TCOs precursors to obtain very homogeneous films, wich were evaluated for application to semiconductor devices by d.c. current-voltage (I-V) analysis. To determine the optimum manufacturing parameters, we varied the temperature of the substrates (borosilicate glass) during the deposition from 250 ºC to 400 ºC, the number of deposited layers (from 1 to 5), the deposition time of each layer (from 5 to 150 s), different network pressures (0,7 and 2 bar), the solution concentration (from 0,5 % to 30 % w/w) and the Al:Zn molar ration (from 5 % to 30 %), for AZO fims. Thermally vacuum evaporated aluminum electrodes with different aspect ratios (1/18, 2/9, 5/13, 5/9 and 8/9) were used to determine the sheet resistance over the whole film area. To determine the electrical conductivity of the films it was necessary to perform atomic force microscopy analysis (AFM) to discover the thickness of the films. Thermogravimetric analysis (TGA) and infrared analysis (FTIR) were also used to verify the formation of the metal oxide phase of the compounds and the X-ray diffraction analysis (XRD) was used to identify which structure formed in the films. / CAPES: 1633460.

Ce manuscrit présente des études expérimentales sur l'évaporation de gouttes et la chimiotaxie de la mite.Une première partie s'intéresse à l'évaporation de spray dense au moyen d'une nouvelle approche, par analogie avec le mélange scalaire. Dans cette limite de forte densité en gouttes, où il y a saturation en vapeur au sein des structures constituantes, l'évaporation est principalement fonction de l'étirement auxquelles ces structures sont soumises. C'est en effet celui-ci qui conditionne le taux d'évacuation de cette vapeur interstitielle, ce qui permet de mettre les gouttes en contact avec un environnement plus sec, déclenchant ainsi leurs évaporations.Une deuxième partie s'intéresse à une application de la compréhension de cette dynamique d'évaporation de spray dense à un contexte d'entomologie: la chimiotaxie de la mite. Il s'agit du processus par lequel l'animal va se repérer dans un champ de concentration, pour localiser la source d'une substance attractive par exemple (ici de la phéromone sexuelle). Cette partie a tendu vers l'obtention d'une visualisation conjointe de la trajectoire de l'animal et du champ de concentration sous-jacent par la visualisation des gouttes. / This thesis present some experiments on droplets evaporation and moth chemotaxis.In a first part, dense spray evaporation is explained through a new approach, drawing an analogy with scalar mixing. In this high density droplets limit, where vapor saturation is reached within the structures, evaporation is mainly controlled by the intensity at which these structures are stretch. It is indeed the stretching that controls the rate at witch interstitial vapor is evacuated: droplets are thus in contact with a dryer environment, so they can start to evaporate.A second part take an interest in applying dense spray evaporation dynamic understanding to an entomologist situation: moth chemotaxis. This is the process by which animals find their way in a concentration field, such at finding a chemoattractant source for instance (sexual pheromone in our case). This part tended towards visualizing animal trajectory and concentration field underlying through droplets visualization simultaneously.

L’atomisation assistée est un procédé de formation d’un spray de gouttelettes issu d’une nappe liquide sous l’action d’un courant gazeux à forte vitesse dans un injecteur. Ce procédé est très utilisé dans de nombreuses applications industrielles. Nous étudions la succession d’instabilités hydrodynamiques qui génère les gouttes du spray à l’aide d’une méthode LIF pour mesurer la fréquence des vagues et d’une sonde optique pour la granulométrie des gouttes. Nous validons expérimentalement un nouveau modèle de stabilité linéaire inviscide pour l’instabilité de cisaillement, intégrant un profil de vitesse avec déficit à l’injection. Des simulations numériques et un modèle spatio-temporel de stabilité linéaire sont utilisés pour mettre en avant de nouveaux mécanismes de déstabilisation, de croissance des vagues et de création de gouttes. Les lois d’échelles connues prédictives du diamètre moyen des gouttes en fonction du Weber gaz sont testées pour de nouvelles variables d’étude. / Assisted atomization is a process used to form a spray of droplets. A slow liquid phase is strippedby the action of a strong gas current in order to generate the spray. This process is used in manyindustrial applications. We study the succession of hydrodynamic instabilities generating dropletsby means of a LIF method to measure the frequency and growthrate of waves, and with an opticalprobe to measure drop size and velocity. We validate experimentally a model including an interfacialvelocity deficit in the inviscid stability analysis. Experiments are compared to numerical simulationsand spatiotemporal stability analysis results : the confrontation of these three approaches is used tobring forward new mechanisms of destabilization, growth of waves and creation of drops. We assessthe influence of liquid thickness and dynamic pressure ratio on the dependency of the mean dropletdiameter with the Weber number.

The objective of this study is to investigate the feasibility of depositing 1.5 mm thick titanium coatings, as a repair method for aerospace Ti-6Al-4V substrates, using two new commercially available processes: Low Pressure Cold Spray (LPCS) and Pulsed Gas Dynamic Spray (PGDS). The coatings produced were examined and characterized by their porosity level, microhardness, adhesion strength, particle flattening ratio, wipe tests, fracture surface type and wear tests. Phases and chemical composition were determined using X-Ray diffraction analysis and energy dispersive spectroscopy, respectively. It was found that both spraying processes are capable of producing dense, hard and oxide-free coatings using specific parameters. Finally, as a first step towards repair implementation of these processes, damages were simulated on Ti-6Al-4V samples, which were successfully repaired with low porosity and high hardness levels. The feasibility of repairs was confirmed, the next step will consist in qualification testing to assess coating performances under real life application.