With the amalgamation of hard coating in cutting tools industries for three decades now, a stage with proven performance has been reached. Today, nearly 40% of all cutting tools used in machining applications are sheltered with coatings. Coatings have proven to dramatically improve wear resistance, increase tool life and enable use at higher speed. Over the years TiN, TiAlN and TiC have emerged as potential materials to coat machining tools. Chemical vapor deposition was the first technology to be used to deposit these coatings followed by physical vapor deposition. Currently, extensive use is being made of cathodic arc evaporation and sputtering for coatings components. The principal limiting factor in the performance of these cutting tools lies in their failure due to the brittleness of these coatings. These hard coatings, usually coated on soft steel substrates, are subjected to contact damage during service. This contact damage is driven by mismatch strain between the elastically deforming film on a plastically deforming substrate. Understanding of the contact damage is the key parameter for improvement in the coating design. Contact damage involves initiation of cracks and subsequent propagation within coating. Multiple cracking modes are seen in nitride coatings on soft substrate and mutual interaction of cracks may lead to spallation of the coating, exposing the substrate to extreme service conditions. Hence visualization of subsurface crack trajectories facilitates the classification of benign and catastrophic modes of failure, which consequently allows us to tailor the coating architecture to eliminate catastrophic failure. Multilayers have shown to perform better then monolayer coatings. In multilayer coatings, application specific particular properties can be engineered by alternately stack-ing suitable layers. The multilayer utilizes benefits of interfaces by crack deflection, crack blunting and desirable transition in residual stress across the interface. Hence, designing interfaces is the key parameter in the multilayer coating. However, very few studies exist that describe experimental visualization of deformation modes in multilayer coatings with different types of interfaces, e.g. nitride/nitride and nitride/metal. Thus the prime objective of the present study is to comprehend the influence of different interface structures as well as its architecture on the various contact damage modes in these coatings. TiAlN/TiN has shown better tribological properties compared to its constituent monolayers. There is an order of magnitude augmentation in loads for cracking without any hardness enhancement relative to monolayers of constituents, with the additional feature that both constituents exhibit similar hardness and modulus. The resistance to cracking is seen to increase with increase in number of interfaces. Hence this uniqueness in toughening without drastic reduction in mechanical properties provides the motivation for understanding the fundamental mechanisms of toughening provided by the interfaces in these hard/hard coatings. Another combination for the present study is with interfaces between hard-soft phases ZrN/Zr, a composite that seeks to compromise hardness in order to achieve greater toughness. The selected combination has potential of providing a model system without any substoichiometric nitrides influencing the interfacial structure. There is a great need to optimize the metal fraction/thickness for exploiting the benefits of toughening without much compromise on hardness and stiffness, since the principal applications of these coatings lies in preventing erosive and corrosive wear. As all the deformation modes in theses coatings are stress driven, the influence of different variables on stress field would dictate the emerging damage. To understand the role of stress fields on contact damage, finite element method and an analytical model was used to predict the stress field within the coating. The TiAlN/TiN coatings were deposited by cathodic arc evaporation, while sputtering was employed to procure the ZrN/Zr multilayer coatings with much finer layer spacing. Microstructural characterization of the as received coatings was done by XRD, scanning electron microscopy, focused ion beam cross section machining and transmission electron microscopy. Mechanical properties like hardness and modulus were evaluated by nanoindentation with restricted penetration depths to allow measurements that were not influenced by the substrate. Contact damage was induced by micro indentation at high loads. Indentations were examined from plan view as well as cross section for getting details of crack nucleation as well as propagation trajectories. Focused ion beam was used to examine cross sections of indents as well as to prepare electron transparent thin foils for transmission electron microscopy examination of subsurface damage induced by indentation. To emphasize specific issues in detail, the present work is divided into four sections: 1 Microstructure and mechanical characterization of the as deposited coatings of ZrN/Zr multilayer (while that of TiAlN/TiN has been reported elsewhere) 2 Details of contact damage in ZrN/Zr coating 3 Resolution of micro mechanistic issues in TiAlN/TiN coating utilizing detailed microscopy 4 The effect of change in architecture through heat-treatment of ZrN/Zr multilayer coatings on the mechanical behavior and contact damage Detailed microstructural, compositional and mechanical characterization was done on ZrN/Zr as received multilayer coatings. Thickness of metal layer was seen to influence the texture in the nitride, thick metal acquiring basal texture in turn inducing (111) texture in the nitride to reduce interfacial energy. Microstructure revealed that the nitride grows with interrupted columnar grains, renucleating at each metal/nitride interface. Presence of both phases was confirmed at even very low bilayer spacing, with slight changes in multilayers architecture, from planar interfaces to curved interfaces. The chosen system proved to be an ideal system for multilayer study without formation of secondary nitrides. Residual stress and hardness reduced with increase in metal layer thickness, whereas modulus was seen to follow the rule of mixture value. Detailed contact damage study of ZrN/Zr is reported in section two with influence of volume fraction and metal layer thickness. All the experimental results were corroborated with finite element methods. A comparative study of contact damage of multilayer with monolayer was carried out with cross section as well as plan view of indents. Metal plasticity was able to distribute damage laterally as well as vertically, hence reducing the stress concentration. There lies an optimum thickness of the metal providing maximum toughening by increasing the threshold load required for edge cracking. The sliding of columns is resisted by the metal. However, thick metal layers promote microcracking in individual nitride layers. Cracking is restricted to within individual nitride layers, eliminating through thickness cracking. The intermediate metal thickness was able to provide a mechanism of laterally distributing sliding and hence a higher tolerance level of the indentation strain that can be accommodated without cracking. Thin metal multilayers were seen to show delamination, strongly influenced by the multilayer architecture. We use the finite element method to understand the influence of stress fields in driving these various modes of damage for varying volume fraction and metal layer thicknesses. It is demonstrated how metal plasticity results in stress enhancement in the nitride layer compared to a monolayer and reduces the shear stress, which is the driving force for columnar sliding. The micro cracking to columnar shearing transition with metal thickness was explained with the help of average shear and normal stress across the multilayer which could explain the transition from cracking and sliding to interfacial delamination in thin metal layer multilayers with enhancement in interfacial shear stress. TiAlN/TiN multilayer allowed to exploit a form of compositional contrast to measure the strain with respect to depth. Layers acting as strain markers quantify the amount of sliding in terms of the offset in layers with respect to depth within the coating. We illustrate with transmission electron micrographs, the flaw generation that occurs as a result of sliding of misaligned column boundaries. These boundary kinks,upon further loading, may lead to cracks running at an angle to the indentation axis in an otherwise dense, defect free, as deposited coating. A previous study illustrates the increase in resistance of multilayers to multiple modes of cracking that are seen in the monolayer nitride coatings on steel substrates. We provide evidence of the enhanced plasticity, seen as macroscopic bending, which in reality is column sliding in a series of distributed small steps. We discuss the role of misfit dislocations in spreading the material laterally to accommodate the constraints during indentation and lattice bending. Interfacial sliding is seen to reduce the stress concentration by distributing the vertical column sliding and accommodating the flaws generated by the sliding of misaligned column boundaries. Some preferred boundaries with special orientation relations do slide, while near the substrate, the sliding is facilitated by the relaxation in intrinsic residual stresses. An analytical model which was formulated earlier is used to support our experimental findings. Investigations of the plausible reasons for the naturally occurring multilayer mollusc sea shells to reach stiffnesses equal to the upper bound of the rule of mixture value have concluded that its brick and mortar organization is responsible for its exceptional mechanical properties. Inspired by the same model, heat treatment was used to change the architecture of the soft-hard metal/nitride combination from that of the planar interface of the as deposited multilayer to a brick and mortar arrangement. Such an interconnected ZrN microstructure was successfully achieved and the stiffness and hardness were both seen to increase relative to the as received coatings. The possible reasons for this enhancement are discussed in term of this newly emerged architecture ,change in residual stress as well as changes in stoichiometry after heat treatment. The contact damage, though, was found to be more catastrophic relative to the as deposited coating with increased propensities for edge and lateral cracking. This was attributed to the interconnected nitrides formed in the brick and mortar architecture as well as residual stress changes due to the dissolution of Zr in ZrN to form off-stoichiometric nitrides. The cracks feel the presence of the metal and deviate from the otherwise smooth trajectory and take a path along the interface of the metal packet and the interconnected nitride. Summarizing, the present study clearly illustrates the fact that interfaces play an important role in damage control under contact loading. Fracture and deformation are either controlled by metal plasticity, distributing the column sliding in metal/nitride multilayers or by interfacial sliding mediated by interfacial misfit dislocations in case of the nitride/nitride multilayer coatings. The effective role of interfaces is to distribute damage laterally as well as horizontally to relieve stresses and hence enhance the damage tolerance under indentation. Optimum metal layer thickness has been proposed for maximum toughening in the metal/nitride multilayer coating and the role of interfaces in providing modes of plasticity is presented for the nitride/nitride multilayer coatings by use of extensive transmission electron microscopic investigations. A new interconnected architecture coatings provides a unique way of combining stiffness and toughness along with scope for further developing such configurations with improved mechanical properties.

Cette thèse se place dans le cadre d’un projet ANR qui vise à remplacer des dépôts électrolytiques sacrificiels par des dépôts PVD à base d’aluminium, moins néfastes pour l’environnement. Trois critères ont été définis :un comportement sacrificiel avec de faibles cinétiques de dissolution, une bonne résistance au grippage et la possibilité d’élaboration du dépôt avant emboutissage du substrat acier. Des revêtements monocouches ont été élaborés pour étudier l’effet d’un élément d’alliage dans l’aluminium. Certains éléments (Mo, Mn) améliorent les propriétés mécaniques et d’autres (Mg, Zn) les propriétés sacrificielles des revêtements. Cette étude a permis de mettre en évidence qu’il est difficile de combiner de bonnes propriétés mécaniques et sacrificielles. Pour pallier à ce problème, deux voies peuvent être explorées. L’élaboration d’alliages ternaires et celle d’architectures multicouches.Ce travail s’est focalisé de manière plus approfondie sur la deuxième voie. Des architectures multicouches ont été élaborées avec deux types de couches, chaque type de couche possédant l’une des deux propriétés souhaitées pour le revêtement. Les configurations étudiées sont les suivantes : Al-Mo/Al-Zn, Al-Mo/Al-Mg et Al-Mn/Al-Mg, avec différentes périodes. Cette étude a permis de trouver une architecture multicouche qui répond tout à fait aux deux premiers critères :Al-Mn/Al-Mg 15 nm.Une étude préliminaire en corrosion après déformation a été réalisée sur cette dernière. Elle perd son caractère sacrificiel en immersions salines de 48h à partir de 1% de déformation. L’optimisation des paramètres de dépôt pour améliorer la tenue mécanique de cette architecture est une prochaine étape. / This work is part of an ANR project which purpose is to find an alternative to sacrificial electrolytic coatingsusing aluminium-based PVD coatings, which are more environmental friendly. Three main parameters weredefined : a sacrificial behavior, good tribological properties and the possibility to elaborate the coatings before shaping the steel substrate. Monolayer coatings were elaborated to study the impact of an alloying element on aluminium properties. Some alloying elements increase mechanical properties (Mo, Mn) while others enhance the electrochemical behavior (Mg, Zn). To combine both properties, two methods can be used. Either the elaboration ofternary alloys or the elaboration of multilayer coatings. This work is focused on the second way. Some multilayercoatings were proposed with two types of layers, each type presenting one interesting property. This study permitted to find a multilayer architecture fitting very well two parameters required for the project.A preliminary study on this architecture was lead with electrochemical characterization after strain. The architecture loses its sacrificial behavior after 1% strain in 48h immersion. Two of the three requested criteria are found.The next step of this work would be the optimization of the process parameters to enhance the adhesion of the coating so the third parameter is achieved.

O presente trabalho tem como objetivo contribuir para o conhecimento da morfologia, microestrutura e modulação composicional (perfil da composição química) de recobrimentos NbN/CrN multicamadas nanoestruturados com diferentes periodicidades (entre 4 e 20 nm) depositado por PVD pela técnica de arco catódico. Foi alcançada espessura total do recobrimento de 30 ?m mantendo-se a homogeneidade da periodicidade ao longo de toda a espessura. Análises de difração de Raios-X, aliadas a modelamento computacional (difração dinâmica), e análise de microscopia eletrônica de transmissão (MET), permitiram a determinação da periodicidade das multicamadas e a espessura das camadas individuais de NbN e CrN e análise qualitativa da coerência entre as camadas. O modo de varredura (SMET) acoplado com espectroscopia de perda de energia de elétrons (EELS), permitiu medir a variação da composição química ao longo das nano-camadas individuais. A análise por EELS mostrou que, mesmo para a menor periodicidade estudada - 4nm, não há eliminação da modulação composicional. Assim, um modelo de Análise de Elementos Finitos (FEA) foi utilizado para avaliar a componente das tensões residuais intrínsecas ao longo das multicamadas, alimentado com o cáculo da deformação do parâmetro de rede, que pela Lei de Vergards varia em função da modulação química, ao longo das camadas de NbN e CrN. A microindentação instrumentada e o teste de riscamento mostraram aumento de dureza e maior resistência ao risco com a redução da periodicidade das multicamadas nanoestruturadas de NbN/CrN. O cruzamento dos resultados das diversas técnicas empregadas permitiu análise detalhada da estrutura e morfologia destes recobrimentos e a influência das periodicidades na modulação química das camadas individuais, possibilitando o desenvolvimento de um modelo qualitativo. Este aprendizado irá permitir a deposição de recobrimentos multicamadas nanoestruturados com melhor controle das propriedades mecânicas objetivadas em função da aplicação final do produto. / The present work aims at contributing to the knowledge, microstructure and compositional modulation (Chemical composition profile) of NbN/CrN multilayer nanostructured coatings with different periodicities (between 4 and 20nm) deposited by cathodic arc technique. It was reached a total coating thickness of 30 ?m preserving the periodicity homogeneity along the thickness. X-Ray Diffraction analisys, combined with computational modeling (dinamic diffraction) and Transmission Eletron Microscopy analysis (TEM), allowed the multilayer periodicity determination, the individual NbN and CrN layer thicknesses as well as the qualitative analysis of coherency among layers. The scanning mode (STEM) combined with Electron Energy Loss Spectroscopy (EELS), allowed the measurement of the chemical composition variation along the individual nanolayers. The EELS analysis showed that, even for the lowest periodicity studied - 4nm, there is no elimination of the compositional modulation. Thus, the Finite Element Analysis model (FEA) was used to evaluate the intrinsic residual stress component along the multilayers, fed with the lattice parameter deformation calculation, which, by Vegards Law varies as a function of the chemical modulation, along the NbN and CrN layers. The instrumented microindentation and the Scratch test showed hardness increase and higher scratch resistance as periodicity decreases on the nanostructured multilayer of NbN/CrN. The cross-linking data of the several techniques employed enabled a detailed analysis of the structure and morphology of such coatings and the influence of the periodicities on the individual layer chemical modulation, allowing the development of a qualitative model. This learning will allow multilayer nanostructured coatings deposition with a better control of desired mechanical properties as a function of the final product application.

O presente trabalho tem como objetivo contribuir para o conhecimento da morfologia, microestrutura e modulação composicional (perfil da composição química) de recobrimentos NbN/CrN multicamadas nanoestruturados com diferentes periodicidades (entre 4 e 20 nm) depositado por PVD pela técnica de arco catódico. Foi alcançada espessura total do recobrimento de 30 ?m mantendo-se a homogeneidade da periodicidade ao longo de toda a espessura. Análises de difração de Raios-X, aliadas a modelamento computacional (difração dinâmica), e análise de microscopia eletrônica de transmissão (MET), permitiram a determinação da periodicidade das multicamadas e a espessura das camadas individuais de NbN e CrN e análise qualitativa da coerência entre as camadas. O modo de varredura (SMET) acoplado com espectroscopia de perda de energia de elétrons (EELS), permitiu medir a variação da composição química ao longo das nano-camadas individuais. A análise por EELS mostrou que, mesmo para a menor periodicidade estudada - 4nm, não há eliminação da modulação composicional. Assim, um modelo de Análise de Elementos Finitos (FEA) foi utilizado para avaliar a componente das tensões residuais intrínsecas ao longo das multicamadas, alimentado com o cáculo da deformação do parâmetro de rede, que pela Lei de Vergards varia em função da modulação química, ao longo das camadas de NbN e CrN. A microindentação instrumentada e o teste de riscamento mostraram aumento de dureza e maior resistência ao risco com a redução da periodicidade das multicamadas nanoestruturadas de NbN/CrN. O cruzamento dos resultados das diversas técnicas empregadas permitiu análise detalhada da estrutura e morfologia destes recobrimentos e a influência das periodicidades na modulação química das camadas individuais, possibilitando o desenvolvimento de um modelo qualitativo. Este aprendizado irá permitir a deposição de recobrimentos multicamadas nanoestruturados com melhor controle das propriedades mecânicas objetivadas em função da aplicação final do produto. / The present work aims at contributing to the knowledge, microstructure and compositional modulation (Chemical composition profile) of NbN/CrN multilayer nanostructured coatings with different periodicities (between 4 and 20nm) deposited by cathodic arc technique. It was reached a total coating thickness of 30 ?m preserving the periodicity homogeneity along the thickness. X-Ray Diffraction analisys, combined with computational modeling (dinamic diffraction) and Transmission Eletron Microscopy analysis (TEM), allowed the multilayer periodicity determination, the individual NbN and CrN layer thicknesses as well as the qualitative analysis of coherency among layers. The scanning mode (STEM) combined with Electron Energy Loss Spectroscopy (EELS), allowed the measurement of the chemical composition variation along the individual nanolayers. The EELS analysis showed that, even for the lowest periodicity studied - 4nm, there is no elimination of the compositional modulation. Thus, the Finite Element Analysis model (FEA) was used to evaluate the intrinsic residual stress component along the multilayers, fed with the lattice parameter deformation calculation, which, by Vegards Law varies as a function of the chemical modulation, along the NbN and CrN layers. The instrumented microindentation and the Scratch test showed hardness increase and higher scratch resistance as periodicity decreases on the nanostructured multilayer of NbN/CrN. The cross-linking data of the several techniques employed enabled a detailed analysis of the structure and morphology of such coatings and the influence of the periodicities on the individual layer chemical modulation, allowing the development of a qualitative model. This learning will allow multilayer nanostructured coatings deposition with a better control of desired mechanical properties as a function of the final product application.

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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 namely / reflective 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.

Du fait de leurs excellentes propriétés mécaniques et de leurs faibles masses spécifiques, l’utilisation des matériaux composites, au sein des structures mécaniques, est en plein essor. Cependant, leur usinage entraine une usure prématurée et aléatoire des outils de coupes en cermet WC-Co. L’origine de cette étude provient de la nécessité de protéger leur surface par un revêtement dur et résistant comme, par exemple, le diamant NCD. Toutefois, le cobalt présent dans le carbure cémenté favorise la formation de graphite au niveau de l’interface avec le film de diamant, ce qui nuit à son adhérence. La méthode retenue afin d’isoler ce métal de la surface a été de réaliser des systèmes interfaciaux multicouches. Ces derniers sont composés d’une barrière de diffusion au cobalt en nitrure de tantale et/ou en nitrure de zirconium et d’une couche favorisant la germination du diamant en acier inoxydable ou en molybdène. Les protocoles de dépôt élaborés au cours de ce travail ont la particularité d’utiliser une polarisation négative et séquencée du substrat durant l’étape de croissance. Cela induit une morphologie originale au revêtement de diamant breveté sous le nom de PyrNCD (Brevet N° :FR0807181). Les objectifs de cette étude sont la compréhension de l’ensemble des mécanismes (influence de la solubilité du carbone sur la germination du diamant, l’effet de la polarisation sur le substrat revêtu et sur la croissance du diamant,…) intervenant durant le dépôt de diamant et l’optimisation du procédé. / The combination of good mechanical properties and low specific mass ensures the increasing use of composite materials to reduce the weight of mechanical structures. However, their machining induces premature and random wear of WC-Co cermet cutting-tools. The origin of this study comes from the necessity to protect cutting-tools surfaces by hard and resistant coatings like NCD diamond. Unfortunately, the cobalt found in these cemented carbides catalyses graphite formation at the interface with the diamond layer and harms the grip of the diamond film. The method used to isolate this metal from the surface has been to form interfacial multilayer systems. These are composed of a tantalum nitride and/or zirconium nitride diffusion barrier for cobalt and a layer promoting the diamond nucleation in molybdenum or stainless steel. The deposit protocols developed during this PhD work have the particularity of using a negative and sequenced substrate bias during the growth stage. This leads to an original morphology of the diamond coating which is patented under the name PyrNCD (International Patent N°: WO/2010/076423). The goal of this study is to understand all the mechanisms (like the impact of the carbon solubility on the diamond nucleation, the effects of negative bias on the coated substrate and the diamond growth,...) occurring during diamond deposition and process optimization.

Dans ce travail de thèse on étudie le développement de revêtements monocouches (simple couche) et multicouches à base de nickel en utilisant des techniques humides (électrodéposition et dépôt chimique dynamique). L'objectif principal est d'obtenir un revêtement d'une dureté élevée (supérieure à 500 HV) et une bonne résistance à la corrosion (plus de 500 heures en brouillard salin), sur la base des exigences de l'industrie aéronautique, principalement le groupe SAFRAN. Dans la première partie nous présentons le développement de revêtements de Ni par la technique d'électrodéposition. À partir d’un bain électrolytique de sulfamate avec différentes concentrations de samarium, nous avons obtenu un revêtement avec une résistance à la corrosion élevée. L'utilisation d'un bain électrolytique avec un additif de diméthyle amine borane (DMAB) conduit à un revêtement avec une dureté élevée. Ainsi, nous avons prépare un revêtement multicouche acier/Ni (Sm)/Ni-B, pour obtenir un dépôt avec bonne résistance à la corrosion (proportionné par la couche de Ni électrolytique obtenu à partir d’un bain avec samarium) et une dureté élevée (proportionné pour la couche Ni-B électrolytique). En outre, en employant la technique de dépôt chimique dynamique (JetMetal) on a obtenu un revêtement de Ni-B ayant une dureté élevée et un revêtement composite de Ni-B-PTFE avec de bonnes propriétés tribologiques. Finalement nous avons élaboré un revêtement multicouche acier /Ni (Sm)/NiB-SDS/NiBPTFE à partir des technologies de dépôt électrochimique et la technique JetMetal, le revêtement obtenu présente une bonne résistance à la corrosion, une dureté élevée et un faible coefficient de frottement. / In this thesis work we investigate the development of monolayer coatings (single layer) and nickel-based multilayers by using wet techniques (electrodeposition and dynamic chemical deposition). The main objective is to obtain a coating with high hardness (above 500 HV) and good corrosion resistance (over 500 hours in salt spray), based on the requirements of the aviation industry, mainly the SAFRAN group. The first part of this thesis examines the development of Ni coatings by using electrodeposition technique. From an electrolytic sulfamate bath with different samarium concentrations, can be obtained coatings with high resistance to corrosion, while the use of an electrolytic bath with dimethyl amine borane (DMAB) leads to a coating with high hardness. The development of multilayer coatings in an alternated way using two electrolytic baths (with different composition), was realized to take advantage of the individual properties of each deposit. Thus the steel/Ni (Sm)/Ni-B multilayer coating was obtained, in order to be use the good corrosion resistance of Ni layer obtained from a bath with samarium and the high hardness of a Ni-B coating. On the other hand, by employing the dynamic chemical deposition technique (JetMetal), Ni-B coating with high hardness and a composite coating Ni-B-PTFE with good tribological properties could be obtained. Finally, a multilayer coated steel/Ni(Sm)/NiB-SDS/NiB-PTFE was developed by combining the electroplating technology and dynamic chemical deposition technique, the obtained coating showed good corrosion resistance, high hardness and a low friction coefficient. / En este trabajo de tesis se investiga la elaboración de recubrimientos monocapa (una sola capa) y multicapas a base de níquel mediante el empleo de técnicas vía húmeda (electrodepósito y depósito químico dinámico). El objetivo principal es de obtener un recubrimiento con alta dureza (superior a 500 HV) y buena resistencia a la corrosión (superior a 500 h en cámara salina), en base a los requerimientos de la industria aeronáutica, principalmente el grupo SAFRAN. En la primera parte de esta tesis se estudia la elaboración de recubrimientos de Ni mediante el empleo de la técnica de electrodepósito. A partir de un baño electrolítico de sulfamato con diferente concentración de samario, se puede obtener un recubrimiento con alta resistencia a la corrosión. En tanto que el uso de un baño electrolítico con el aditivo dimetil amina borano (DMAB) permite obtener un recubrimiento con alta dureza. La elaboración de recubrimientos multicapas mediante el uso alternado de dos baños electrolíticos de composiciones diferentes, permite aprovechar las propiedades individuales de cada depósito. Así se elaboró un recubrimiento multicapa acero/Ni(Sm)/Ni-B, para aprovechar la buena resistencia a la corrosión de una capa de Ni obtenida a partir de un baño con samario y la dureza elevada de un recubrimiento Ni- B. Por otra parte, mediante el empleo de la técnica de depósito químico dinámico (JetMetal) fue posible obtener recubrimiento Ni-B con alta dureza y un recubrimiento compuesto Ni-B-PTFE con buenas propiedades tribológicas. Finalmente se elaboró un recubrimiento multicapa acero/Ni(Sm)/NiB-SDS/NiB-PTFE mediante el empleo combinado de la técnica de electrodepósito y la técnica de depósito químico dinámico, que presenta una muy alta resistencia a la corrosión, una alta dureza y un bajo coeficiente de fricción.