The diploma thesis deals with the virtual commissioning of robotized workplace for cold spraying. The theoretical part of the thesis contains an overview of the current state of knowledge in the field of virtual commissioning, the theory of crating HMI user environments, deals principles of the Rapid programming language as a tool for controlling industrial robots and analysis of robotic workplace components. The practical part defines the structure of the proposed user program and user environment, which are created using software tools Robotstudio and Screenmaker. The last part discusses in detail the steps during the implementation of the created program together with the HMI into commission, which is associated with the testing of functionalities on a real device for cold spraying. The diploma thesis also includes a user manual created for operating an industrial robot.

Memoria para optar al título de Ingeniero Civil Mecánico / Cold spray es una técnica de deposición de material en donde partículas impactan a altas velocidades sobre un sustrato con el objetivo de generar un recubrimiento para refuerzo o reparación de superficies, para aplicaciones en la industria aeroespacial principalmente. Dada la escala nanotemporal del proceso, existe una gran dificultad para medir experimentalmente las deformaciones y temperaturas alcanzadas durante el impacto, por lo que se hace necesario apoyar los estudios experimentales con simulaciones numéricas. En este trabajo se estudia la micro dureza Vickers de un recubrimiento de aluminio 1100 sobre un sustrato de aluminio 6061-T6. El objetivo del trabajo es determinar la capacidad del modelo computacional para predecir la dureza del material recubierto mediante cold spray. Por una parte, el estudio se lleva a cabo mediante mediciones experimentales de microdureza Vickers con 0.05, 0.1 y 0.2 kgf de carga de indentación. Por otra parte, se utiliza el programa ABAQUS para realizar simulaciones con elementos finitos con el método explícito y el enfoque Lagrangiano para el impacto de múltiples partículas. De las simulaciones, se obtiene la deformación de las partículas y se determina su influencia en el endurecimiento por deformación plástica del material a través del modelo de plasticidad de Johnson-Cook. Con este modelo se calcula el esfuerzo de fluencia por endurecimiento y se relaciona dicho esfuerzo con la dureza del material mediante relaciones empíricas. En las simulaciones, el tamaño de partícula utilizado es de 25 m y la velocidad de impacto es de 600 m/s, ambos datos obtenidos a partir de mediciones en el proceso de formación del recubrimiento. Los resultados de las simulaciones son comparados con las mediciones experimentales y se observan grandes diferencias entre la dureza simulada y la dureza medida, con errores entre 28.6% y 66.2%. A pesar de ello, se comprueba que hay endurecimiento en el recubrimiento debido al impacto de las partículas, tal como se ve en la práctica de esta técnica. Se discute como causa de estas diferencias la configuración espacial de las partículas en el impacto y un posible ablandamiento térmico del recubrimiento luego de su formación experimental.

MCrAlY coatings are commonly applied as the bond coat in TBCs used in modern gas turbines. Cold spray (or CS), characterized by low process temperature and high particle impact velocity, has been demonstrated as a promising alternative to thermal spray processes, such as air plasma spray (APS) and high velocity oxygen fuel (HVOF), for manufacturing MCrAlY coatings. The general objective of the thesis research is to characterize CS deposition on a single-crystal nickel-base superalloy and to develop low-cost/high-performance NiCoCrAlTaY coatings using the CS technique. Several individual studies were carried out with each having a specific focus towards achieving the general research objective. CS deposition of NiCoCrAlTaY coatings using nitrogen was first examined to verify the feasibility of replacing the expensive helium gas typically used as the CS process gas. Several materials were used as the substrates, and the effects of substrate materials and surface preparation on coating microstructure and properties were investigated. Recycling of non-deposited powder particles was then explored to reduce the costs associated with the feedstock powder. A cost model that includes the economics of powder recycling was developed for the CS process, showing that the use of nitrogen and powder recycling could potentially be cost-effective for CS deposition of MCrAlY coatings. A CS process that can produce in-situ nanocrystalline NiCoCrAlTaY coatings was proposed to develop coatings with enhanced oxidation performance. This CS approach utilizes conventional commercial powders instead of pre-milled nanocrystalline powders. Detailed characterization using the scanning electron microscope (SEM), scanning transmission electron microscope (STEM), and X-ray diffraction (XRD) was carried out to investigate the microstructure of the resulting CS NiCoCrAlTaY coatings, single-crystal substrate, and their interface. Isothermal oxidation performance of the CS NiCoCrAlTaY coatings was evaluated at 1100°C for 1h to 500h. Results revealed that the nanostructure promoted the α-Al2O3 scale formation and sustained α-Al2O3 scale growth, suggesting good isothermal oxidation performance. Finally, the effects of different processing sequences on CS NiCoCrAlTaY coating characteristics and short-term isothermal oxidation performance were investigated. Specifically, CS deposition of NiCoCrAlTaY coatings was carried out on single-crystal superalloy substrates that underwent various degrees of full heat treatments prior to being coated. The remaining superalloy heat treatments required were then performed on the coated samples after the CS deposition. The microstructures of the superalloy substrates and CS NiCoCrAlTaY coatings were characterized after each heat treatment. Isothermal oxidation performance of the coated samples following different sequences was evaluated at 1100°C for 2 hours. The results suggested a promising processing sequence that could potentially further improve the oxidation performance of CS NiCoCrAlTaY coatings.

Cold spray is an additive manufacturing method in which powder particles are accelerated through a supersonic nozzle and impinged upon a nearby substrate, provided they reach their so-called critical velocity. True to its name, the cold spray process employs lower particle temperatures than other thermal spray processes while the particle velocities are comparably high. Because bonding occurs mostly in the solid state and at high speeds, cold spray deposits are distinguished for having low porosity and low residual stresses which nearly match those of the bulk material. One complication with the cold spray process is the tendency for nozzles to clog when spraying (in general) low-melting-point or dense metal powders. Clogging occurs when particles collide with the inner nozzle wall and bond to it rather than bouncing off and continuing downstream towards the substrate. The particles accumulate and eventually plug the nozzle passage. Clogging is inconvenient because it interrupts the spraying process, making it impossible to complete a task. Furthermore, when particle buildup occurs inside the nozzle, the working cross-sectional area decreases, which decreases the flow velocity and therefore the particle velocity, ultimately jeopardizing the particles’ ability to reach critical velocity at the substrate. In this work, computational fluid dynamics (CFD) is used to study various aspects of nozzle clogging. Nozzle cooling with supercritical CO2 as the refrigerant is investigated as a means to prevent clogging. The effects of nozzle cooling on both the driving gas and the particles are addressed. Simplified pressure oscillations at the nozzle inlet are imposed to determine whether such oscillations, if present, can cause clogging. Subsequently, more realistic and complicated flow oscillations are introduced to isolate a potential root cause of clogging. Finally, several novel nozzle internal geometries are evaluated for their effectiveness at preventing clogging. A recommendation is provided for a nozzle to be tested experimentally because it might completely prevent clogging.

Particle-laden supersonic jets impinging on a flat surface are of interest to cold gas-dynamic spray technology. Solid particles are propelled to a high velocity through a convergent-divergent nozzle, and upon impact on a substrate surface, they undergo plastic deformation and adhere to the surface. For given particle and substrate materials, particle velocity and temperature at impact are the primary parameters that determine the success of particle deposition. Depending on the particle diameter and density, interactions of particles with the turbulent supersonic jet and the compressed gas region near the substrate surface can have significant effects on particle velocity and temperature. Unlike previous numerical simulations of cold spray, in this dissertation we track solid particles in the instantaneous turbulent fluctuating flow field from the nozzle exit to the substrate surface. Thus, we capture the effects of particle-turbulence interactions on particle velocity and temperature at impact. The flow field is obtained by direct numerical simulations of a supersonic rectangular particle-laden air jet impinging on a flat substrate. An Eulerian-Lagrangian approach with two-way coupling between solid particles and gas phase is used. Unsteady three-dimensional Navier-Stokes equations are solved using a six-order compact scheme with a tenth-order compact filter combined with WENO dissipation, almost everywhere except in a region around the bow shock where a fifth-order WENO scheme is used. A fourth-order low-storage Runge-Kutta scheme is used for time integration of gas dynamics equations simultaneously with solid particles equations of motion and energy equation for particle temperature. Particles are tracked in instantaneous turbulent jet flow rather than in a mean flow that is commonly used in the previous studies. Supersonic jets for air and helium at Mach number 2.5 and 2.8, respectively, are simulated for two cases for the standoff distance between the nozzle exit and the substrate. Flow structures, mean flow properties, particles impact velocity and particles deposition efficiency on a flat substrate surface are presented. Different grid resolutions are tested using 2, 4 and 8 million points. Good agreement between DNS results and experimental data is obtained for the pressure distribution on the wall and the maximum Mach number profile in wall jet. Probability density functions for particle velocity and temperature at impact are presented. Deposition efficiency for aluminum and copper particles of diameter in the range 1 micron to 40 microns is calculated. Instantaneous flow fields for the two standoff distances considered exhibit different flow characteristics. For large standoff distance, the jet is unsteady and flaps both for air (Mach number 2.5) and for helium (Mach number 2.8), in the direction normal to the large cross-section of the jet. Linear stability analysis of the mean jet profile validates the oscillation frequency observed in the present numerical study. Available experimental data also validate oscillation frequency. After impingement, the flow re-expands from the compressed gas region into a supersonic wall jet. The pressure on the wall in the expansion region is locally lower than ambient pressure. Strong bow shock only occurs for small standoff distance. For large standoff distance multiple/oblique shocks are observed due to the flapping of the jet. The one-dimensional model based on isentropic flow calculations produces reliable results for particle velocity and temperature. It is found that the low efficiency in the low-pressure cold spray (LPCS) compared to high-pressure cold spray (HPCS) is mainly due to low temperature of the particles at the exit of the nozzle. Three-dimensional simulations show that small particles are readily influenced by the large-scale turbulent structures developing on jet shear layers, and they drift sideways. However, large particles are less influenced by the turbulent flow. Particles velocity and temperature are affected by the compressed gas layer and remain fairly constant in the jet region. With a small increase in the particles initial temperature, the deposition efficiency in LPCS can be maximized. There is an optimum particle diameter range for maximum deposition efficiency. / Ph. D.

Des travaux récents ont montré que des revêtements polymères étaient réalisables par procédé connu sous le nom de Cold-Spray. Ces travaux sont particulièrement importants pour le polyéthylène de très haute masse molaire (UHMWPE) qui ne peuvent pas être mis en forme par les méthodes conventionnelles. Mais les mécanismes d'obtention des dépôts n'avaient pas été analysés. Cette thèse présente une analyse expérimentale mécanique détaillée du comportement à l'impact de particules d'UHMWPE et des mécanismes de formation du revêtement polymère sur un substrat en aluminium (Al) sous l'effet de la pulvérisation à froid de ces particules. La formation du revêtement se décompose en deux étapes : (1) se rapporte à la formation de la première couche de particules (interaction polymère-substrat), (2) à la croissance (par ajout de couches successives) du revêtement polymère (interaction polymère-polymère). La première étape de la formation du revêtement a été étudiée grâce à une technique expérimentale développée dans le cadre de cette thèse et appelée "Méthode de dépôt de particules isolées" (IPD). Il s'agit de déposer des particules isolées de UHMWPE sur un substrat en Al, en utilisant la même machine Cold-Spray, tout en contrôlant de manière précise la température du gaz et la teneur en FNA. Grâce à l'utilisation d'une caméra rapide, il a été possible de déterminer la vitesse des particules d'UHMWPE et par le calcul d'évaluer leur température avant et pendant leur impact. L'efficacité augmente avec d'une part la température et d'autre part la fraction de FNA. Cette efficacité dépend de la compétition entre l'énergie cinétique stockée sous forme d'énergie élastique Eel et l'énergie d'adhésion Ead du polymère à la surface du substrat. Pour que le film polymère se forme, il faut que Ead > Eel. Par ailleurs, Ead dépend de l'interface entre polyéthylène et aluminium, et de la présence de FNA. Les liaisons H disponibles sur la surface des FNA contribuent à l'adhésion, ce qui augmente le domaine de température favorable à la réalisation du dépôt. Concernant la croissance du revêtement, il s'agit cette fois-ci de l'adhésion polyéthylène-polyéthylène, avec toujours l'effet des nanoparticules FNA. Les études microstructurales et mécanique ont montré qu'en frittage conventionnel du UHMWPE sous forte pression, l'ajout de FNA renforce la cohésion des matériaux obtenus, mais que l'effet inverse est observé pour un frittage incomplet (sous faible pression). Enfin, afin d'explorer l'effet de vitesse de sollicitation de l'UHMWPE comparable à celles observées pour le Cold-Spray, des expériences utilisant des barres dites de Split-Hopkinson (SHPB) ont été menées. Les courbes obtenues permettent de disposer d'une cartographie complète du comportement thermo-viscoélasto-plastique de ce polymère, pur ou additionné de FNA. / Recent developments showed polymer coatings to be feasible by cold spray (CS) technique on different surfaces. This is especially important for Ultra-High Molecular Weight Polyethylene (UHMWPE) which cannot be classically processed. But the mechanisms behind coating formation was not largely understood. The thesis presents a mechanistic understanding of high strain rate impact behavior of Ultra-High Molecular Weight Polyethylene and the mechanism of coating formation during CS. The coating formation is first broken down into two major categories: 1. Interaction of UHMWPE with Al substrate (impacting particle-substrate interaction) during a high-speed impact and interaction of UHMWPE with already deposited UHMWPE particles (impacting particle-deposited particles) leading to a buildup in the coating. First stage of coating formation was understood from a technique developed for this work called Isolated Particle Deposition (IPD). In the experimental IPD process, effects of gas temperature and FNA content were calibrated empirically by depositing UHMWPE particles in an isolated manner on an Al substrate. The Deposition efficiency increased with gas temperature and FNA content. The use of an ultrafast video-camera helped to determine the particle velocity, and theoretical calculations helped to evaluate the temperature of UHMWPE particles before and during the impact process. Mechanical response of UHMWPE at different temperatures were understood by calculating elastic strain energy of UHMWPE which decreased with increasing material temperature and increased with the strain rate. Rebound of UHMWPE particles on Al surface depended upon whether UHMWPE particles after impact furnished a contact area with an interfacial bond stronger than elastic strain energy of the particle. External contributions like H-bonds on the FNA surface provide sufficiently strong extra bonds at the contact surface to increase the window of deposition at higher temperatures, which was otherwise very low. Second stage of coating formation was understood from the mechanism of welding of UHMWPE grains at different interfacial loading conditions and at varying FNA contents. The morphological and mechanical characterization showed that when UHMWPE was processed under high loading conditions (using classical sintering technique), FNA particles reinforced the UHMWPE interface. On the contrary, when UHMWPE was processed under low loading conditions, FNA particles weakened the interface. Last to be discussed in the thesis is the strain rate effect of UHMWPE using Split-Hopkinson Pressure Bar (SHPB) experiments, in order to approach comparable conditions to what happens during particle impacts. This part of the study discussed in detail the effects a high strain-rate compression has on UHMWPE by analyzing its stress-strain curves, with and without FNA. Thus, the mechanical response data with the inclusion 0%, 4% and 10% FNA to UHMWPE is also presented and discussed.

La projection thermique cold spray consiste en l'envol de poudres à haute vitesse sur une cible : le substrat. Leur adhérence et leur accumulation mène à des revêtements plus ou moins denses, utilisés dans le domaine automobile, biomédical, etc. La première étape de construction du dépôt passe par un contact entre la poudre et le substrat. Il est admis que la liaison créée est mécanique et, si la nature des matériaux le permet, métallurgique. Cette étude permet de statuer sur ces deux composantes. Pour cela, deux systèmes privilégiant l'une ou l'autre, sont choisis. L'ancrage mécanique est vu au travers de la métallisation de polymère avec l'emploi d'aluminium projeté sur polyamide 6,6. La liaison métallurgique est abordée avec l'emploi de titane sur un substrat plus rigide en TA6V. Avant d'étudier les mécanismes de liaison, une étape d'élaboration des dépôts est réalisée balayant de nombreux paramètres « procédé » et différentes propriétés des matériaux (température, granulométrie). Des outils sont déployés pour connaître les conditions d'impact : la vitesse de particule par DPV2000, la température du substrat par thermographie infra-rouge et la température des particules par voie numérique. L'ancrage mécanique dans le polymère est décrit grâce à l'étude de l'impact de particules élémentaires ainsi que de la rugosité d'interface 2D (coupes micrographiques) et 3D (laminographie X). Le gradient de porosité est également quantifié. La liaison métallurgique est étudiée par MET. Au préalable, la simulation numérique par éléments finis est employée pour retracer la phénoménologie de l'impact ainsi que quantifier les déformations et les températures locales atteintes à l'interface. La morphologie simulée des particules à l'impact est comparée à celles observées dans des conditions réelles de projection. Enfin, l'adhérence des différents dépôts est évaluée par essai « plot collé » et les faciès de rupture observés. L'influence de la morphologie de surface est étudiée avec des prétraitements de sablage et de structuration laser. / Cold Spray consists in the high-speed spray of powder particles onto a target; namely the substrate. Their adhesion and accumulation leads to a more or less dense coating to be used in the automotive, the biomedical… areas. The first stage of coating results from a powder to substrate contact. Bonding is due to mechanical anchoring and, depending on the involved materials, to metallurgical interaction. This study helps to rule on these two components. For this, two systems, which promote either mechanical or metallurgical mechanism separately, are selected. Mechanical anchoring is studied through polymer metallization using of aluminum for spraying onto polyamide 6,6. Metallurgical bonding is studied using titanium onto Ti-6Al-4V. Before studying the bonding mechanisms, the spraying process is investigated using many process parameters and materials properties (temperature, particle size…). Advanced tools are employed to determine impact conditions; i.e. particle velocity by DPV2000, substrate temperature by infrared thermography and particle temperature by numerical calculation. Mechanical anchoring onto the polymer is described through the analysis of elementary particle impacts and through 2D (micrograph sections) and 3D (laminography) study of interface roughness. The porosity gradient is also quantified. Metallurgical bonding is studied by TEM. Before that, a finite element simulation is used to go into the phenomenology of the impact and to quantify the local deformation and temperature at the interface. The simulated particle morphology is compared to those observed in real spraying conditions. Lastly, deposit adhesion is assessed by pull-off testing and the fractured surface is observed. The influence of the substrate surface morphology is exhibited using sand-blasting and laser structuring pretreatments.

Le domaine automobile utilise des alliages légers d’aluminium dans la fabrication des pièces volumineuses du moteur thermique afin d’améliorer son rendement énergétique. Cependant, leurs propriétés sont insuffisantes pour pouvoir faire face aux contraintes thermomécaniques du moteur en service qui requièrent des matériaux à haute performance. Une solution innovante est l’application d’un revêtement par projection par gaz froid dite « cold spray » à base d’acier inoxydable AISI 316L aux dimensions et aux propriétés adaptées aux sollicitations locales. Ce procédé repose sur la projection à haute vitesse de particules de poudre sur un substrat, qui, déformées en « splats » à l’impact, adhérent pour créer un revêtement. Cette étude a pour ambition de comprendre les mécanismes d’endommagement thermomécanique de revêtements cold spray composites à base de 316L. Pour cela, les étapes de l’élaboration des revêtements, les paramètres de projection et les poudres de l’étude sont détaillés. Des revêtements de 316L pur sont réalisés ainsi que des analyses microstructurales par microscopie optique, MEB, chimiques par EDX et cristallographiques par EBSD et DRX, afin d’étudier l’influence du procédé cold spray sur la poudre initiale. Les interfaces entre les splats, constituants majeurs dans la cohésion des revêtements, sont étudiées en détail au MET. Puis, des éléments d’addition moins durs de cuivre et plus durs d’alliage de nickel Tribaloy 700 (Ni700), sont incorporés dans les mélanges de poudres avec l’acier afin de créer des revêtements composites. La modification de la microstructure et de la qualité des interfaces par la création de matériaux composites est alors abordée. Enfin, ces matériaux sont éprouvés et comparés grâce à des essais quasi statiques de dureté et de traction, et dynamiques d’impact-glissement. Les résultats et les observations locales de la réponse de la microstructure à ces sollicitations macroscopiques permettront d’envisager les mécanismes d’endommagement de ces revêtements cold spray. / Aluminum alloys are commonly used in the automotive industry for lightening and power gain of thermal engines. However, thermomechanical properties are not often high enough to undergo the in-service stresses while the engine is running. High performance materials are needed. A novel approach to reach these high performances is to develop specific coatings using the cold spray route. This thermal spray process is based on the plastic deformation of sprayed powders at a supersonic velocity onto a substrate resulting in so called « splats » and stick to the surface. In this thesis, thermomechanical damage of cold-sprayed 316L-matrix composite coatings are studied. Prior to the study of composites, the elaboration steps of 316L in the cold spray coatings are established. Powder and coatings are studied to determine the influence of the cold spray process. Microstructural analyse involved optical microscopy, SEM, chemical analysis EDX and image analysis. Cristallographic analyse were performed by EBSD and DRX. Interfaces between splats are specifically studies by TEM. These consist of a crucial actor in the cohesion of coatings. Then, softer powder of Cu and harder powder of Ni700 are mixed with 316L and cold sprayed to build composite coatings. Their influence on the microstructure through the creation of new interfaces is observed. Last but not least, mechanical properties of the different coatings are compared. Hardness and tensile tests are used for quasi-static loading characterization whereas impact-sliding tests are used for dynamic loading characterization. Results and the local observation of the microstructural response to these macroscopic loadings give an insight into major damage mechanisms of cold sprayed composite coatings.

La réalisation de revêtements métalliques en surface de matériaux composites à matrice organique est possible par le procédé cold spray. La construction de tels revêtements à partir de particules de cuivre sur un substrat contenant des fibres de carbone n'a pu aboutir que grâce à l'ajout d'une poudre polymère. Malgré son rôle dans la construction des dépôts, le polymère présente le désavantage d'être un très bon isolant électrique ayant, de ce fait, une influence très néfaste sur la conductivité des dépôts cold spray. Ces travaux ont donc été concentrés sur l'étude de l'influence de la microstructure de ces dépôts sur leur conductivité électrique. Plusieurs poudres de cuivre ont été mélangées dans diverses proportions avec du PEEK, un polymère thermoplastique. La projection cold spray de ces mélanges a abouti à la formation de dépôts homogènes sur les substrats composites. L'influence des caractéristiques des poudres et des paramètres de projection sur les caractéristiques des dépôts a été étudiée. De même, la déformation du PEEK lors de la projection a été analysée car elle joue un rôle important dans la construction du dépôt. L'étude des propriétés mécaniques du PEEK et des conditions de projection ont permis de simuler sa déformation. Dans la microstructure du dépôt, la présence du PEEK limite les contacts entre les particules de cuivre, abaissant fortement la conductivité électrique des dépôts. Un modèle morphologique de la microstructure a été développé afin d'étudier l'influence de la morphologie de la phase de cuivre sur la conductivité des dépôts. Ce modèle a permis de simuler des microstructures présentant diverses morphologies en 3 dimensions. Il ouvre ainsi la possibilité d'étudier numériquement l'influence de la morphologie de la microstructure des dépôts sur leur conductivité électrique. La conductivité a été mesurées expérimentalement sur des échantillons de dépôt. Un mélange de poudre et des paramètres optimaux ont alors pu être identifiés pour obtenir un dépôt cold spray sur un substrat composite à matrice organique avec une conductivité satisfaisante mais encore inférieure à celle du cuivre massif. / The Cold Spray process allows to manufacture metallic coatings onto Carbon Fiber-Reinforced Composite (CFRP). This process relies on the spraying of high-velocity powder particles to result in high deformation and build up to form a dense coating. However, forming a coating made of copper particles onto a substrate containing carbon fibers was achieved out only by mixing metallic powder with a polymer powder. Although the polymer allow to build up the coating onto CFRP, it is highly electrically insulating. It would therefore decrease the electrical conductivity of the coating drastically. Investigations were carried out on the influence of the coatings microstructure on electrical conductivity. Various copper powders, with different morphologies, granulometry and oxygen contents were mixed with PEEK powder, i.e. a thermoplastic polymer. Cold spray of these powders leads to homogeneous coatings onto CFRP. The characteristics of these coatings were studied as a function of the influence of powder characteristics and spraying parameters. The deformation of the PEEK was also investigated as it governed the build up of the coating. Mechanical testing of PEEK samples and in-situ spraying measurements were performed to feed impact simulations. Then, simulated and experimental impact morphologies of copper particles onto PEEK were compared. The PEEK behavior under impact also prevented sound contacts between copper particles, which decreased the coatings electrical conductivity significantly. A morphological model of the microstructure of the coating was developed to reproduce microstructures in 3D numerically. It allows to investigate numerically the influence of the copper phase morphology on coating conductivity. This conductivity was measured experimentally for various starting copper powders. A carefully selected blend of copper and PEEK powders and optimized spraying parameters lead to homogeneous coatings onto CFRP with an acceptable electrical conductivity but still below bulk copper conductivity.

The objective of this study is to successfully deposit Titanium Ti-6Al-4V layers onto Ti-6Al-4V substrate using two new commercially available Cold Spray processes such as Low Pressure Cold Spray (LPCS) and Pulsed Gas Dynamic Spray (PGDS). The second objective of this work is to develop a technique to repair Titanium parts since there is currently no repair technique commercially available. It is envisioned that commercial cold spray systems could be used to repair gashes on Titanium components. The examination of both feedstock powders and coatings were performed by different techniques such as optical microscopy and Scanning Electron Microscopy (SEM). Porosity, hardness, adhesion strength, flattening ratio, wipe test, fracture surface, wear test, XRD and chemical composition of the coatings using EDS have been evaluated. Cold spray has shown to be a promising technique for the deposition of heat sensitive particles such as titanium. LPCS and PGDS both produced high quality coatings. Low porosity, high hardness, adhesion strength over 40 MPa, metallurgical bonding, similar to bulk material wear rate, no oxide and nitride phases inside coating were measured.