The purpose of the present PhD research project was to evaluate the feasibility of the electrodeposition of novel thin Ni composite coatings with lubricant particles from an additive-free Watts bath and their application as diffusion barrier layers in journal bearings for medium-speed diesel engines. Overall, the main objective was to develop thin Ni composite coatings with the following characteristics: • Improved tribological performance. • Good adhesion properties. • Good ‘anti-diffusion’ performance. Ultrasound was used in the preparation of pure Ni coatings and Ni composite coatings with lubricant particles under different conditions in order to understand how ultrasonic cavitation influences electrodeposition and characteristics of said Ni-based coatings. Two main studies were conducted related to this: 1. Study of the effect of ultrasonic power on the electrodeposition of pure Ni coatings to understand the influence of cavitation phenomena near the surface of the cathode on the properties of Ni deposits 2. Study of the effect of ultrasound on the production of Ni composite coatings to understand the influence of ultrasound in the dispersion of particles, the electrodeposition of Ni composite coatings and the properties of said Ni composite coatings. The influence of ultrasound on the dispersion of particles in the Watts bath was evaluated by observing the visual appearance of the resulting dispersions and analysing the particle size distribution of diluted solutions by laser diffraction-based particle sizing methods. The effect of ultrasound on the characteristics of Ni deposits and Ni composite coatings electrodeposited from the additive-free Watts bath was evaluated by different material characterization techniques: Abstract • X-Ray Diffraction (XRD) analysis was employed to observe the orientation of the Ni crystals that formed the coatings. • Field Ion Beam – Scanning Electron Microscopy (FIB-SEM) was employed to analyse the surface morphology and microstructure of the coatings. • Microhardness tests were performed to observe how the modification of the grain structure and the presence of particles may affect the hardness of the coatings. • Glow Discharge – Optical Emission Spectroscopy (GD-OES) was also employed to estimate the particle content in the Ni composite coatings.

The void spaces in colloidal crystals (opals, three-dimensional (3D) close-packed arrays of silica nanospheres) and their replicas are used as templates in the fabrication of new nanostructured materials. 3D ordered nanomeshes and nanosphere arrays are readily obtained by chemical and/or electrochemical methods. Using silica opal templates, metals or polymers are infiltrated into the interstices between the silica nanospheres. Subsequent dissolution of the opals with HF solution produces open 3D mesh structures. Metal (such as Ni, Co, Fe, Pd, Au, Ag, and Cu) and conductive polymer (such as polyaniline) meshes are obtained by electrochemical deposition approach, while the nonconductive polymer (such as poly(methyl methacrylate) (PMMA)) meshes are synthesized by chemical polymerization method. Some new types of meshes are fabricated by the conversion of metal meshes and polymer meshes. NiO meshes are formed by oxidizing Ni meshes in the air. The NiO meshes exhibit higher volume occupation fraction than Ni meshes and the nanocrystalline sizes of NiO particles can be adjusted by the oxidation temperature. Due to the mechanical flexibility of polymer meshes, the compression of PMMA meshes produces deformed PMMA meshes which contain oblate pores. These meshes can be again served as templates to prepare new types of colloidal crystals (nanosphere arrays) and specific nanocomposites. By the use of poorly conductive NiO mesh or PMMA mesh arrays as templates, 3D periodic metal nanosphere arrays, such as those of Ni, Co, Au and Pd, are readily fabricated by the electrodeposition method. Metal/NiO or Metal/PMMA composites can also be obtained if the templates are left intact. The magnetic behavior of metal (such as Ni and Co) meshes and sphere arrays has been investigated. These nanoscale arrays show significantly enhanced coercivities compared with bulk metals, due to the size effect of the nanometer dimensions of the components in meshes and sphere arrays. Angle-dependent magnetic properties of Ni and Co sphere array membranes exhibit out-of-plane anisotropy.

In this study, template-based methods are used for the fabrication of various nanostructures such as nandots, nanorods, nanowires, nanotubes, and core-shell structures. Porous alumina membranes were employed as templates and metal nanostructures were synthesized in the templates by electrodeposition. By using lithography techniques, controlled patterned nanostructures were also fabricated on alumina templates. The magnetic properties of the various metal nanostructures were investigated. The pore size, interpore distance, and pore geometry highly affect magnetic properties of nanostructures grown in the templates. Hexagonally ordered porous alumina templates can be fabricated by two-step anodization. The pore diameters and interpore distances were readily controlled by appropriately changing anodization conditions and pore widening time. Alumina templates with various pore geometries were also successfully synthesized by changing applied voltage, increasing and decreasing, during a third anodization step. To understand magnetic properties of nanostructures with different aspect rations in the form of nanodots, nanorods, or nanowires, Fe nanostructures were fabricated in the templates by controlling of electrodeposition times. The coercivity of nanostructures increased with increasing aspect ratio. The anisotropy of the arrays was governed by the shape anisotropy of the magnetic objects with different aspect ratios. nanowires in mild-hard alumina and conventional alumina templates showed distinct differences in the squareness of hysteresis loops and coercivity both as a function of pore structure and magnetic component. Iron oxide nanotubes with a unique inner-surface were also fabricated by an electrodeposition method. β-FeOOH nanotubes were grown in alumina templates and transformed into hematite and magnetite structures during various heating processes. Hematite nanotubes are composed of small nanoparticles less than 20 nm diameters and the hysteresis loops and FC-ZFC curves show superparamagnetic properties without the Morin transition. In the case of magnetite nanotubes, which consist of slightly larger nanoparticles, hysteresis loops show ferromagnetism with weak coercivity at room temperature while FC-ZFC curves exhibit the Verwey transition at 125 K. For the patterning of nanowires, lithography techniques including nanosphere lithography and e-beam lithography were used. Nanosphere lithography used self-assembled PS spheres as a mask creates holes between spheres and the size of the holes is determined by the size and geometry of ordered PS spheres on the templates. This method can grow patterned nanowires arrays and also produce unique cup-shaped nanostructures with sizes ranging from micrometer down to several nanometers. E-beam lithography was also combined with template-based electrodeposition. Of these two lithographic methods, this one is the most powerful in the fabrication of patterned nanostructures with high aspect ratios. Various features and the sizes of patterned structures can be readily controlled. By the directing the pore diameters and interpore distances of the alumina template, the size and number of patterned nanowires are also adjustable.

A deposição eletroquímica, ou eletrodeposição, é uma técnica amplamente utilizada na obtenção de recobrimentos metálicos. A presença de certos compostos químicos (aditivos) nos banhos eletrolíticos pode influenciar o processo de eletrodeposição de maneira significativa. A glicina é um aminoácido presente em muitos banhos para a eletrodeposição de filmes finos de ligas de cobalto, que são interessantes devido às suas propriedades magnéticas. As propriedades de algumas ligas à base de cobalto obtidas a partir de banhos contendo glicina já foram bem descritas, mas há falta de estudos mais específicos sobre o papel do aminoácido no processo de eletrodeposição do cobalto. Esta Tese apresenta estudos realizados na tentativa de compreender a influência da glicina no mecanismo de eletrodeposição do cobalto. Técnicas de análise in situ, envolvendo espectroscopia no infravermelho por reflexão externa e medidas de pH na região próxima a interface via microeletrodo indicador foram acopladas aos estudos eletroquímicos. Depósitos de cobalto de boa qualidade foram obtidos a partir de banhos contendo glicina, e sob condições de sobrepotencial mais elevadas do que as possíveis para sistemas sem aditivos, onde ocorre precipitação de hidróxidos. Análises dos experimentos de voltametria cíclica indicaram a eletroatividade de complexos cobalto-glicina, e cinética de redução mais lenta foi observada, em relação a sistema sem glicina em valores de pH suficientemente elevados. Os estudos cinéticos foram dificultados pela reação de desprendimento de hidrogênio e a existência de diversos equilíbrios químicos em solução. Durante a eletrodeposição de cobalto em soluções contendo glicina, um aumento bastante significativo no pH próximo da interface foi observado. Os experimentos espectroeletroquímicos também demonstraram deslocamento dos equilíbrios químicos de complexação do cobalto em solução, devido ao aumento do pH interfacial. Todos os estudos mostraram que a presença de glicina favorece a reação de desprendimento de hidrogênio, diminuindo a eficiência de corrente do processo de eletrodeposição. Ainda assim, a glicina se mostrou eficaz na estabilização da solução eletrolítica. / The electrochemical deposition, or electrodeposition, is a widely used technique to obtain metallic coatings. The presence of certain chemical species (additives) in plating baths can significantly influence the metal electrodeposition process. Glycine is an aminoacid present in many electrolytic solutions for electrodeposition of cobalt thin films and alloys, which are interesting due to their magnetic properties. The properties of some Co-based alloys obtained from glycine-containing baths are well documented, but studies of the exact role of the aminoacid are lacking. This Thesis presents studies attempting to understand the influence of glycine on the mechanisms of cobalt electrodeposition. In situ analysis techniques - external reflection FTIR spectroscopy and pH measurement near the electrochemical interface using indicator microelectrodes - were coupled to the electrochemical studies. Good-quality cobalt deposits were obtained from glycine-containing baths, and under higher overpotentials than possible over systems with no additive (in which precipitation of hydroxides occurs). Analysis of the cyclic voltammetry experiments indicated the electroactivity of cobalt-glycine complexes, and the slower reduction kinetics in comparison with glycine-free solutions at sufficiently high pH values. The kinetic studies were hindered by the parallel hydrogen evolution reaction and the existence of several chemical equilibria in solution. During cobalt electrodeposition from glycine-containing solutions, an expressive elevation of the near interface pH was observed. The spectroelectrochemical experiments also showed the displacement of cobalt complexation equilibria in solution, caused by the increase in the interfacial pH. All the conducted studies showed that the presence of glycine favors the hydrogen evolution reaction, decreasing the current efficiency for the electrodeposition process. Nevertheless, glycine was able to stabilize the electrolyte solution.

O estudo do eletrorrevestimento de tântalo sobre aço e sobre cobre foi realizado na mistura eutética FLINAK (29,2% LiF - 11,7% NaF - 59,1% KF - % em massa) contendo 15% em massa de K2TaF7. Foram estudadas as influências da densidade de corrente catódica, do tempo de eletrólise, da temperatura e da natureza do substrato sobre as eficiências de correntes catódicas e a morfologia dos revestúnentos. Depósitos de tântalo lisos, brilhantes, aderentes e uniformes foram obtidos com alta eficiência de corrente catódica usando os seguintes parâmetros: densidade de corrente catódica de 23 mA/cm2 a 50 mA/cm2, temperatura de 750°C e tempo de eletrólise de 30 minutos a 120 minutos. Os revestimentos obtidos nestas condições possuem espessuras de 18 µm a 41 µm. Os depósitos de tântalo sobre aço e sobre cobre são constituídos de tântalo puro, sem formação de camada de difusão. Ensaios de eletrodeposição de camadas delgadas de tântalo em catodos de formas e geometrias complexas mostraram o bom poder de cobertura do tântalo. Curvas potencial de circuito aberto x tempo, feitas à temperatura ambiente em soluções de ácido nítrico a 40%, a 50% e a 60% em massa, ácido clorídrico a 3,6% em massa e ácido sulfúrico a 80% em massa, mostraram ótima concordância entre o potencial de circuito aberto estacionário do tântalo maciço comercial e dos revestimentos de tântalo sobre cobre nestes meios. Curvas potencial de circuito aberto x tempo feitas à temperatura ambiente em meio de ácido clorídrico a 3,6% em massa, para revestimentos sobre aço mostraram que a semelhança com o tântalo maciço só é observada em depósitos recentes, o que foi atribuído à difusão do ferro do substrato para a superficie do revestimento. Ensaios gravimétricos mostraram que a velocidade de corrosão dos revestimentos é comparável com a do tântalo comercial, em meios de ácido nítrico a 40% e a 50% em massa, à temperatura de ebulição. / The study of tantalum electroplating on copper and carbon steel has been carried out in FLINAK eutectic (29.2% LiF -11.7% NaF -59.1% KF - wt%) containing 15wt% K2TaF7. The effects of current cathodic density, time of electrolysis, temperature and substrate kind have been studied in relation to the cathodic current efficiencies and the coating morphology. Tantalum deposits, with good smoothness, brightness, adherence and uniformity were obtained with high cathodic efficiency, using the following conditions: 23 mA/cm2 to 50 mA/cm2 cathodic current densities, 30 minutes to 120 minutes electrolysis time interval and 750°C temperature. Under these conditions the coatings are about 18 µm to 41 µm thick. The deposits obtained on carbon steel and copper are both constituted of pure tantalum without formation of interdiffusion layer. The results of tantalum thin coatings electrodeposition on cathodes of complex geometrics and shapes showed the good throwing power of tantalum. Open circuit potential x time curves have been recorded for massive tantalum and for tantalum coatings on copper in 40 wt%, 50 wt% and 60 wt% nitric acid, 3.6 wt% hydrochloric acid and 80 wt% sulfurie acid at room temperature. They showed similar stationary open-circuit poteutial values for both the massive tantalum and the tantalum coatings. Open circuit potential x time curves for tantalum coatings on carbon steel performed in 3.6%wt hydrochloric acid at room temperature showed that the similarity with massive tantalum exists only with recent deposits, because of iron diffusion from substrate to coating surface. Gravimetric tests showed comparable corrosion rate values for massive tantalum and tantalum coatings in boiling 40wt% and 50wt% nitric acid.

O armazenamento de energia em larga escala é um dos maiores desafios que temos que sanar em médio prazo para que tenhamos um impacto importante na matriz energética. As baterias aparecem como fortes candidatas para esta função, porém, é preciso melhorar todos os componentes das baterias, como eletrodos e eletrólitos, para aplicação em larga escala. Líquidos Iônicos (LIs) são interessantes alternativas para a utilização como eletrólito em bateria, pois abrem ampla possibilidades, como a utilização de ânodos metálicos e operação em alta temperatura. Sendo assim, este trabalho apresenta o estudo do uso do LI bis(trifluorometanosulfonil)imideto de N-n-butil-N-metilpiperidínio ([BMP][Tf2N]) na eletrodeposição de Mg utilizando vários procedimentos eletroquímicos e analíticos. A deposição/dissolução de Mg é irreversível quando há água (50 mmol L-1) no sistema, e uma reversibilidade de apenas 7,4 % em sistemas mais secos (5 mmol L-1). Imagens de MEV e espectros de EDS mostram que há Mg na superfície do eletrodo, porém é indicada a formação de um filme passivador. Além disso, também foi estudado o comportamento eletroquímico de Cu no LI [BMP][Tf2N], que apresenta um ânion com boa capacidade de coordenação e no LI tetracianoborato de N-n-butil-N-metilpiperidínio ([BMP][B(CN)4]), que apresenta um ânion com baixa capacidade de coordenação. A propriedade de coordenação tem grande influência na oxidação e corrosão do metal, enquanto que no [Tf2N] há corrosão por pitting e não há passivação do metal, o uso do [B(CN)4] leva a precipitação do sal Cu[B(CN)4], causando a passivação do metal. Além disso, mesmo em baixa concentração de água, há formação de óxido durante a oxidação do metal nos dois LIs. Como a água afeta o comportamento eletroquímico dos LIs, foi realizado um estudo das propriedades físico-químicas do LI bis(trifluorometanosulfonil)imideto de 1-n-butil-2,3-dimetilimidazólio ([BMMI][Tf2N]) e sua mistura com Li+ com diferentes quantidades de água. A presença de Li+ causa um grande aumento na capacidade do LI hidrofóbico em absorver água. Experimentos sugerem que há uma quebra nos agregados Li+-ânion, que foi confirmado por dinâmica molecular (DM). Ainda, a água apresenta grande modificação nas propriedades como densidade, viscosidade e condutividade iônica, sem contar que os resultados experimentais sugerem uma quebra na regra de Walden em altas temperaturas. Por fim, foi avaliado a estrutura local do LI tetracianoborato de 1-n-butil-2,3-dimetilimidazólio ([BMMI][B(CN)4]), para entender como é a interação entre o ânion de baixa capacidade de coordenação e o Li+. A distância entre os ânions e o Li+ é maior do que no caso do [Tf2N], indicando assim uma menor interação entre estes dois. A utilização de LIs como eletrólitos para baterias se apresenta como alternativa promissora, porém ainda demanda estudos para encontrar o melhor sistema. / Energy storage at large scale is one of the most important challenges that needs to be solved in medium term to have an important impact in the electrical grid. Batteries seem to be strong candidates for this function, however, it is needed to improve all battery components, as electrodes and electrolytes, to be applied in large scale. Ionic Liquids (ILs) are interesting alternatives to be used as electrolyte in a battery, since they open a wide range of possibilities, as the use of metallic anodes and operation at high temperature. This work presents the study of electrodeposition of Mg using the IL N-butyl,methyl-piperidinium bis((trifluoromethyl)sulfonyl)imide ([BMP][Tf2N]) by several electrochemical and analytical techniques. The deposition/dissolution is irreversible in presence of high water concentration (50 mmol L-1), and a small reversibility of 7.4 % in dryer system (5 mmol L-1). EDS spectra show Mg presence in the electrode surface, however it is also observed the formation of passivating film. Besides this, it was also studied the electrochemical behavior of Cu in the IL [BMP][Tf2N], which presents a strong coordinating anion and in the IL N-butyl,methyl-piperidinium tetracyanoborate ([BMP][B(CN)4]), which presents a weak coordinating anion. It was observed that the oxidation and corrosion of Cu depends strongly on the anions coordinating properties, while on [Tf2N] it was observed pitting corrosion and no metal passivation, the use of [B(CN)4] leads to salt (Cu[B(CN)4]) precipitation, causing the metal passivation. It was also observed that even at low water concentration there is the formation of oxide in both ILs. As the water affects the electrochemical behavior of the ILs, it was realized a study of the physicochemical properties of the IL 1-Butyl-2,3-dimethylimidazolium bis((trifluoromethyl)sulfonyl)imide ([BMMI][Tf2N]) and its mixture with Li+ with different amounts of water. The Li+ presence provokes a huge increase in the water absorption ability of the hydrophobic IL. Experiments suggest that there is a break in the Li+-anion aggregates, which was confirmed by molecular dynamics (MD) simulations. In addition, water causes important changes in properties as density, viscosity and ionic conductivity; moreover, the experimental results suggest a break in the Walden\'s rule at high temperatures, due to aggregates modification. Lastly, it was evaluated the local structure of the IL 1-Butyl-2,3-dimethylimidazolium tetracyanoborate ([BMMI][B(CN)4]), to understand how a weak coordinating anion and the Li+ interact. It was showed by MD simulations that this property results in a bigger distance between anion and Li+ than in the case of [Tf2N], indicating a lower interaction between both. The use of ILs as electrolytes for batteries is a promising alternative, however it is needed more studies to find the best system.

O objetivo principal deste trabalho é aplicar complexos de cobre(II), níquel(II), zinco(II) e nióbio(V) como fontes de metais em banhos de eletrodeposição. Os íons metálicos foram coordenados aos ligantes íon oxalato, íon citrato, etilenodiamina (EDA) ou tetraetilenopentamina (TEPA), os quais são aditivos orgânicos típicos em banhos de eletrodeposição. Os complexos foram caracterizados por análise elementar, espectroscopias nas regiões do infravermelho e ultravioleta-visível e voltametria cíclica. Foram realizadas eletrólises em presença de dois complexos de coordenação em ausência de quantias adicionais de aditivos, usando aço 1010 como substrato a pH = 4.5 (H2SO4/Na2SO4), resultando em depósitos com dois elementos metálicos. Os depósitos apresentaram aspectos morfológicos com boas qualidades e sem falhas. Em adição, os depósitos foram analisados por EDX, reflectância difusa e espectroscopia de raio-X e também foram realizadas medidas de curvas de polarização. Os depósitos obtidos a partir dos complexos gerados ex-situ mostraram morfologias melhores do que depósitos obtidos de soluções preparadas com os sais dos metais na presença dos aditivos, mediante as mesmas condições de trabalho. É sugerido que os metais de partida, coordenados a aditivos influenciam o processo de eletrodeposição, propiciando depósitos com potenciais de corrosão deslocados por até +200 mV em 0.5 mol.L-1 NaCl (1 mV.s-1). / The main goal of this work is to use copper(II), nickel(II), zinc(II) and niobium(V) complexes as metal plating source in electrodeposition baths. The metal ions were coordinated with oxalate, citrate, ethylenediamine (EDA) or tetraethylenepentamine (TEPA) as ligands, which are typical organic additives in electroplating. The complexes were characterized by elemental analysis, infrared and ultraviolet spectroscopies and cyclic voltammetry. The electrolyses in presence of two coordination complexes in the baths were carried out in absence of extra amount of additive, using 1010 steel as substrate at pH = 4.5 (H2SO4/Na2SO4). Deposits with two metal elements from the ex-situ generated complexes showed good quality morphologic aspect without crashes. Further, the deposits were analyzed by EDX, diffuse reflectance and X-ray spectroscopy and polarization curves were recorded. The deposits showed better morphologies than deposits obtained from the metal salt solutions in presence of additives under similar conditions. It is suggestive that the starting metal plating coordinated with additives influences the electrodeposition processes, affording deposits with corrosion potentials shifted over +200 mV in 0.5 mol.L-1 NaCl (1 mV.s-1).

Nanoestruturas apresentam algumas propriedades que as diferem dos materiais em escalas maiores, o que abre uma série de possibilidades no campo de aplicação. Um ponto importante em nanotecnologia é o desenvolvimento de métodos adequados para a análise e caracterização de nanoestruturas. Este trabalho estuda o uso de Espectrometria por Retroespalhamento Rutherford (RBS) para a análise e caracterização de micro e nanoestruturas de Cu fabricadas utilizando membranas poliméricas Nuclepore® como moldes. As estruturas foram obtidas através do preenchimento dos poros dessas membranas com Cu por eletrodeposição, crescidas sobre um filme fino de Au com espessuras entre 5nm e 500nm depositado em um lado das membranas por Deposição Física em vácuo (PVD) e reforçado por um substrato espesso de Cu com cerca de 10um depositado sobre o filme de Au. Microscopia Eletrônica de Varredura (SEM) e Espectrometria de Retroespalhamento Rutherford (RBS) foram usadas para caracterizar as amostras. Analisando as amostras com micro e nanocilindros, a mudança do espectro RBS como uma função do ângulo de inclinação da amostra foi estudada usando a abordagem de Metzner et al (2007) generalizada para estruturas 3D em simulações numéricas. O diâmetro das micro e nanoestruturas variam entre 50 e 400nm, enquanto seus comprimentos variam entre 1 e 5um. As análises por SEM forneceram o perfil morfológico local dessas estruturas e estimativas para suas dimensões geométricas. As análises RBS forneceram informações sobre o perfil médio das estruturas provenientes de uma região mais extensa da amostra. / Nanostructured materials have properties that make these materials different from their counterpart in higher scale that opens many novel possibilities and technical applications. One of the main issues in nanotechnology is to develop suitable methods for the analysis and characterization of nanostructures. This works studies the use of Rutherford Backscattering Spectrometry for the analysis of micro and nano copper structures, grown in polycarbonate Nuclepore® membrane templates. The test structures were made by filling the pores of the membranes with copper by electrodeposition grown on top of a thin, 5nm to 500nm gold film, deposited on one side of the membrane by Physical Vapor Deposition (PVD) reinforced by a 10um thick copper substrate deposited on top of the gold film. Scanning Electronic Microscopy (SEM) and Rutherford Backscattering Spectrometry (RBS) were used to characterize the samples. Analyzing the samples with micro and nano cylinders, the change of the RBS spectra as a function of the sample tilt angle, was studied using the approach of Metzner et al (1997) generalized to 3D structures by numerical simulations. Cylinder diameters varied from 50nm to 400nm, while their length varied from 1 to 5um. SEM analysis gives local morphological profile and an estimate for geometrical dimensions. RBS analysis provides large areal information about average geometric parameters of the analyzed structures.

Foram estudados os filmes finos eletrocrômicos de WO3, MoO3 e PEDOT:PSS e aplicados em pequenos dispositivos eletrocrômicos. Os filmes finos de WO3 foram produzidos por meio do processo de eletrodeposição galvanostática a partir de um sol de ácido peroxotungstênico. Realizaram-se dois estudos de eletrodeposição dos filmes de WO3: 1º) produziu-se filmes em diferentes correntes -0,45 -0,50, -0,60 e -1,0 mA com tempo de 600 segundos; 2º) produziu-se filmes variando os tempos de eletrodeposição de 100, 200, 300, 400, 500 e 600 s com corrente de -0,45 mA. O tratamento térmico foi efetuado a 120 ºC por 1 hora. Os filmes de WO3 eletrodepositados com corrente -0,45 mA no tempo de 600 s foram estudados com maiores detalhes. Os filmes com espessura de 140 nm apresentaram mudança na coloração de transparente para azul em resposta a aplicação de potencial de -1,0 a 1,0 V. A variação em transmitância foi medida no visível (λ = 633 nm) resultando em ΔT = 61 %. A densidade de carga foi de 35 mC/cm2 e a estabilidade eletroquímica foi de até 3.000 ciclos. As medidas de difração de raios-X mostraram que a estrutura dos filmes de WO3 é amorfa e as imagens de microscopia eletrônica de varredura (MEV) evidenciaram uma superfície homogênea e sem rachaduras. O filme de PEDOT:PSS depositado por dip-coating apresentou uma espessura em torno de 400 nm, mudança de coloração de azul para transparente com a aplicação do potencial de -1,0 a 1,0 V e ΔT= 50 % para o filme de uma camada. Os filmes de MoO3 foram depositados pela técnica de spin-coating e avaliados conforme o número de camadas (1 a 10 camadas) sendo os melhores resultados foram obtidos para a amostra composta por 9 camadas. Este filme apresentou densidade de carga em torno de 25 mC/cm2 e uma mudança de cor de transparente (T= 80%) para azul (T=38%) após a aplicação de potencial de 1,5 e -1,5 V, respectivamente. Foram confeccionados e estudados dispositivos eletrocrômicos (ECDs) com os filmes finos de WO3 e PEDOT:PSS, eletrólitos poliméricos a base de hidroxipropilcelulose (HPC) e goma gelana (GGLA) e contra eletrodo de CeO2-TiO2. As melhores respostas óticas foram obtidas com o dispositivo eletrocrômico WO3/HPC/CeO2-TiO2, sendo ΔT=29% e a densidade de carga de 12 mC/cm2. A melhor estabilidade em função do número de ciclos de coloração/descoloração de 5.500 foi obtido com o dispositivo eletrocrômico WO3|GGLA-PVP-NHS|CeO2-TiO2 com glicerol. / Electrochromic WO3, MoO3 and PEDOT: PSS thin films were deposited and characterized. WO3 thin films were produced using the galvanostatic electrodeposition process from peroxotungstic acid sol. There were two studies of electrodeposition of WO3 films: 1) films were produced in different streams -0.45 -0.50, -0.60 and -1.0 mA with a time of 600 seconds, and 2) produced films were electrodeposited varying times 100, 200, 300, 400, 500 and 600 s with a current of -0.45 mA. The heat treatment was performed at 120 °C for 1 hour. The WO3 films electrodeposited with -0.45 mA current for 600 s were chosen and studied deeply. These films with a thickness of 140 nm showed change in color from transparent to blue in response to applied potential of -1.0 to 1.0 V. The variation in transmittance was measured at λ = 633 nm, resulting in ΔT = 61%, charge density of about 35 mC/cm2 and electrochemical stability up to 3,000 cycles. X-ray diffractograms showed that the structure of the films is amorphous and scanning electron microscopy (SEM) images showed a homogeneous surface without cracks. The film of PEDOT: PSS deposited by dip-coating had a thickness around 400 nm, color change from blue to transparent upon applied potential of -1.0 to 1.0 V and ΔT = 50% for the one layer film. The MoO3 films were deposited by spin-coating and evaluated as the number of layers (1 to 10 layers) appointing the best results for the sample with 9 layers. This displayed the charge density of around 25 mC/cm2 and a color change from transparent (T = 80%) to blue (T = 38%) after applying the potential of 1.5 and -1.5 V, respectively. Furthermore, the electrochromic devices containing WO3 and/or PEDOT: PSS thin films, polymer electrolytes based cellulose and/or gellan gum and counter electrode of CeO2-TiO2 were assembled and characterized. The best responses of ΔT = 29% and charge density of 12 mC/cm2 were obtained for the electrochromic device with WO3/cellulose/CeO2-TiO2 configuration. However, the best coloring/bleaching stability of 5,500 cycles was obtained with the electrochromic device WO3|GGLA-PVP-NHS|CeO2-TiO2 with glycerol configuration.

De nombreux secteurs industriels ont besoin de matériaux métalliques avec des propriétés de résistance à l'usure et de résistance à la corrosion dans des environnements agressifs ou à des températures élevées très élevées. Ces propriétés spécifiques, notamment mécaniques, électriques, magnétiques et optiques, peuvent être obtenues par la production de couches métalliques. Les revêtements d’alliage ou de métal nanocristallin offrent les caractéristiques de performance souhaitées.L'électrodéposition est un procédé largement utilisé pour fabriquer des revêtements sur des substrats métalliques. La structure et les propriétés des revêtements nanocristallins Co-Mo en font des matériaux prometteurs pour diverses applications. De nos jours, les alliages à base de cobalt sont utilisés dans les avions, l’automobile et l’électronique en raison de leur facilité d’utilisation. En outre, les alliages de cobalt sont largement étudiés en raison de leur utilisation prometteuse pour remplacer les alliages nocifs pour l'environnement dans le corps humain. Les alliages nanocristallins sont utilisés dans de nombreux secteurs industriels, tels que la biologie, l'énergie, la nanotechnologie, l'aviation et bien d'autres.Le but de ce travail est de produire des revêtements nanocristallins de Co-Mo électrodéposés et d'étudier l'effet de la microstructure sur leur résistance à la corrosion dans des solutions physiologiques simulées.Le travail est divisé en cinq chapitres:• Chapitre I. Bibliographie. Aspects métallurgiques de l’ingénierie des surfaces métalliques pour les revêtements nanocristallins de Co-Mo.Dans ce chapitre, les aspects métallurgiques de l’ingénierie de surface des revêtements nanocristallins de Co-Mo sont présentés sur la base des données de la littérature. Différentes méthodes utilisées pour le dépôt de revêtements métalliques sont discutées.• Chapitre II. Echantillons et méthodes et techniques expérimentales.Ce chapitre présente les conditions expérimentales d'électrodéposition pour les revêtements nanocristallins de Co-Mo et les techniques utilisées pour les caractériser.• Chapitre III. Structure, propriétés mécaniques et comportement électrochimique des revêtements nanocristallins Co-Mo.Ce chapitre présente la structure, les propriétés mécaniques et le comportement électrochimique des revêtements nanocristallins Co-Mo déposés sur du cobalt pur.• Chapitre IV. Co-Mo / TiO2 revêtements nano-composites.Ce chapitre présente la structure, les propriétés mécaniques et le comportement à la corrosion des revêtements nano-composites Co-Mo / TiO2 galvanisés sur du cobalt pur.• Chapitre V. Mécanismes de croissance des revêtements nano-composites Co-Mo / TiO2.Ce chapitre étudie la structure des revêtements nanocomposites Co-Mo / TiO2 électrodéposés pour des temps d'électrodéposition courts et longs dans des conditions potentiostatiques sur des électrodes ayant la forme d’un film ou d’un disque.En résumé, des revêtements nanocristallins Co-Mo et des revêtements nanocomposites Co-Mo / TiO2 ont été obtenus par dépôt électrochimique. Leur structure et l'influence de différentes conditions d'électrodéposition sur leur structure ont été étudiées. Leur résistance à la corrosion a été testée dans des solutions physiologiques simulées. De plus, le mécanisme de croissance des couches a été déterminé sur les deux types d'électrodes.Cette thèse a été réalisée sous la forme d'une coopération en Cotutelle entre l'Université des sciences et technologies AGH Stanisław Staszic à Cracovie et l'Université de Bourgogne à Dijon pour promouvoir les relations scientifiques franco-polonaises. Ce travail a été soutenu financièrement par le gouvernement français et l'ambassade de France en Pologne. / Currently, various methods are used in surface engineering for the production of surface layers and coatings on many metal substrates to improve their performance. Different industry sectors are oriented to increase the wear resistance and corrosion resistance of materials that are used in aggressive environments or work at high temperatures. Specific properties, including mechanical, electrical, magnetic and optical, can be achieved by the production of metallic layers. Nanocrystalline and amorphous metal or alloy coatings are unique and offer the desired performance characteristics. They are often characterized by very high strength, associated with the effect of strengthening the edge grain.Electrodeposition is a widely used method of producing coatings on metallic substrates. The structure and properties of Co-Mo nanocrystalline coatings make them promising materials for various applications. Nowadays, cobalt based alloys are used in aircraft, automotive and electronics due to their good usability. In addition, cobalt alloys are widely studied due to their promising use in replacing alloys harmful to the environment or the human body. Nanocrystalline alloys are used in many industrial sectors, such as biology, energy, nanotechnology, aviation and many others.The aim of this work is to obtain electrodeposited Co-Mo nanocrystalline coatings and to investigate the effect of microstructure on their corrosion resistance in simulated physiological solutions.The work is divided into five chapters:• Chapter I. Bibliography. Metallurgical aspects of metal surface engineering for Co-Mo nanocrystalline coatings.In this chapter, metallurgical aspects of surface engineering of Co-Mo nanocrystalline coatings are presented on the basis of literature data. Various methods used for deposition of metallic coatings are discussed.• Chapter II. Samples and experimental methods and techniques.This chapter presents experimental electrodeposition conditions for Co-Mo nanocrystalline coatings and techniques used to characterize them.• Chapter III. Structure, mechanical properties and electrochemical behavior of Co-Mo nanocrystalline coatings.This chapter presents the structure, mechanical properties and electrochemical behavior of nanocrystalline Co-Mo coatings deposited on pure cobalt.• Chapter IV. Co-Mo / TiO2 nano-composite coatings.This chapter presents the structure, mechanical properties and corrosion behavior of Co-Mo / TiO2 nano-composite coatings electroplated on pure cobalt.• Chapter V. Growth Mechanisms of Co-Mo / TiO2 nano-composite coatings.This chapter investigates the structure of Co-Mo / TiO2 nanocomposite coatings electrodeposited for short and long electrodeposition times under potentiostatic conditions on the electrode from pure cobalt-shaped cobalt and pure cobalt electrode in the form of a wire.In summary, nanocrystalline Co-Mo coatings were obtained by electrochemical deposition as well as Co-Mo / TiO2 nano-composite coatings. Their structure and the influence of different electrodeposition conditions on the structure were investigated and their corrosion resistance was tested in simulated physiological solutions. In addition, the mechanism of layer growth was determined on two types of electrodes: a disk-shaped electrode and a wire-shaped electrode.This thesis was carried out in the form of Cotutelle cooperation between the AGH University of Science and Technology Stanisław Staszic in Krakow and the University of Burgundy in Dijon to promote Polish-French scientific relations. This work was financially supported by the French government and the French Embassy in Poland.