Submitted by MARCIA ROVADOSCHI (marciar@unifra.br) on 2018-08-16T20:28:57Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertacao_FabioBonorinoVieira.pdf: 1042169 bytes, checksum: 9005bc8a7b7f41c4b1a750f6f427938e (MD5) / Made available in DSpace on 2018-08-16T20:28:58Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertacao_FabioBonorinoVieira.pdf: 1042169 bytes, checksum: 9005bc8a7b7f41c4b1a750f6f427938e (MD5) Previous issue date: 2015-08-31 / Due to their favorable properties as chemical stability, corrosion resistance, mechanical properties and biocompatibility, titanium and his alloys have been used for the manufacture of implants and prostheses for biomedical purposes. The stability of these metals and alloys is obtained due to a passivation layer of biocompatible titanium dioxide, naturally formed on the surface. In this work, titanium was anodized using potentiodynamic techniques forming a duplex with a film barrier back sheet type with a structure of type nanotubes on top. This film aims to metal passivation or alloy and enhance the characteristics of the material forward to interactions with the physiological environment. Although this oxide film is considered as a protective intermediate layer between the host tissue and the implant, it is considered the defense system a foreign body, and being very thin (only a few nanometers) and unstable under the action of body fluids. The current corrosion of metals and alloy with oxide coating in Ringer's solution increases towards Ti> Nb> Alloy 46.5% m / m Ti. The polished Nb shows high via cell viability and low genotoxicity. The anodized materials exhibit cytotoxicity and genotoxicity. / Devido suas propriedades favoráveis como estabilidade química, resistência à corrosão, propriedades mecânicas e biocompatibilidade, o titânio e suas ligas vem sendo utilizados para a fabricação de próteses e implantes para fins biomédicos. A estabilidade destes metais e ligas é obtida devido a uma camada de passivação biocompatível de dióxido de titânio, formada naturalmente sobre a superfície. Neste trabalho, o titânio foi anodizado utilizando técnicas potenciodinâmicas formando um filme do tipo duplex com uma camada inferior do tipo barreira com uma estrutura do tipo nanotubos na parte superior. Este filme tem como objetivo a passivação do metal ou da liga e potencializar as características dos materiais frente às interações com o meio fisiológico. Embora esse filme de óxido seja considerado como uma camada intermediária protetora entre os tecidos hospedeiros e o implante, ele é considerado pelo sistema imune, um corpo estranho, e sendo muito fino (apenas alguns nanômetros) e instável sob a ação dos fluidos corporais. A corrente de corrosão dos metais e da liga com o recobrimento de óxido em solução de Ringer aumenta no sentido Ti> Nb> liga 46,5 % m/m Ti. O Nb polido apresenta alta viabilidade celular e baixa genotoxidade. Os materiais anodizados apresentam citotoxidade e genotoxidade.

Manufacturing of aircraft parts is often complex and time-consuming, which has led to an increased interest in new manufacturing technologies in the Swedish industry such as additive manufacturing (AM). Additive manufacturing techniques could be a solution to meet the aircrafts’ demand since it contributes to an efficient manufacturing and allows a just-in-time production of complex metal parts in their final shape. However, the use of AM aluminum for aircraft applications is in a development phase and no surface treatment process exists. Thereby, it is of high interest to further investigate surface treatments for AM alloys. Currently at Saab AB, conventional aluminum alloys are generally anodized in tartaric sulphuric acid (TSA) to improve the corrosion resistance and adhesion properties of the metal. On the behalf of Saab AB, there is also an interest in establishing powder coating as a surface treatment. This master thesis’ purpose is to investigate the anodizing and adhesion properties for the two additive manufacturing alloys - AlSi10Mg and ScalmalloyⓇ, and compare it with the conventionally produced Al alloy 2024-T3. The anodization and the powder coating is examined by using following characterization techniques: profilometry, light microscopy, scanning electron microscopy and contact angle measurements. The results from the experimental part indicated successful anodizations for all the alloys and good adhesion properties for powder coating. This research is a first step in contributing to a better understanding of the anodic coating and adhesion properties for the AM samples ScalmalloyⓇ and AlSi10Mg

This work deals with fabrication and examination of optical properties of self-ordered TiO2 and Au quantum dots array and its potential usage in medicine as optical sensor for biomolecules detection. Controlled anodization of Ti through Al2O3 template was chosen as a fabrication method for TiO2 QDs, in case of Au galvanic deposition through Al2O3 template onto beforehand prepared TiO2 QDs or substrate with dimple structure. The influence of anodization and deposition conditions on the final structure of QDs and their emission spectrum is also examined.

Tato diplomová práce je zaměřená na výrobu Au-PANI-Au nanodrátů. Prezentovaná výroba nanodrátů je založená na elektrochemické depozici různých kovů a polymerizaci polyanilínu do porézních šablon z porézní anodické aluminy připravených anodizací hliníku. Teoretická část pojednává o základech elektrochémie a porézní anodické aluminy.

Organic transistors have attracted significant research interest in recent years due to their promises of mechanical flexibility and low-cost fabrication. Possible innovative applications include wearable electronic sensor systems, as well as mass-produced, inexpensive localization tags for logistics. However, the limited charge carrier mobility in organic semiconductor materials, contact resistance at the organic-metal interface and comparably long transistor channel lengths result low-speed organic transistors and low current densities compared with conventional inorganic transistors. The organic permeable base transistor (OPBT) is a disruptive transistor architecture that overcomes some of these drawbacks by providing a vertical transistor channel, which is much shorter than in lateral channel organic transistor devices. Consequently, it has been shown to be the fastest organic transistor to date with a transition frequency of 40 MHz, driving currents up to the kA/cm^2 regime. Nevertheless, the OPBT has not yet reached the application stage and its production has been limited to lab-scale devices deposited onto rigid glass substrates. Issues include low yield, large leakage currents, and unknown reliability of the devices. This work addresses these problems by transferring OPBTs to flexible polymer substrates and introducing a controlled and easily reproducible manufacturing technique for the crucial base oxide layer by electrochemical anodization. The anodization technique allows the creation of defined insulating layers, leading to devices with significantly reduced leakage currents and consequently very large transmission factors of 99.9996%. An investigation into the electrical stability of OPBTs shows that the devices are suitable as switching transistors in active matrix organic light emitting displays (AMOLED). In this application, the OPBT demonstrates its strengths particularly well, because fast operation and high current densities are needed. With this thesis a series of milestones on the path to commercial viability of the OPBT have been reached, making the device fit for large-scale production and integration into flexible electronic circuits, allowing it to drive the bendable organic displays of the future.:1 Introduction 2 Fundamentals 3 Experimental 4 Results – Flexible Devices 5 Results – Anodization of the Base Layer 6 Results – TEM Investigations 7 Results – Electrical Stress Measurements 8 Conclusion and Outlook / Durch die Aussicht auf mechanische Flexibilität und kostengünstige Herstellung haben Organische Transistoren in den vergangenen Jahren erhebliches Forschungsinteresse geweckt. Innovative Anwendungsideen umfassen tragbare elektronische Sensorsysteme und massenproduzierte, preiswerte Ortungsetiketten für die Logistik. Leider führen die geringe Ladungsträgermobilität in organischen Halbleitermaterialien, Kontaktwiderstände am Organik-Metall-Übergang und vergleichsweise große Kanallängen der Transistoren dazu, dass organische Transistoren langsamer sind und geringere Stromdichten aufweisen als anorganische Transistoren. Der Organic Permeable Base Transistor (Organischer Transistor mit durchlässiger Basis, OPBT) stellt eine bahnbrechende Transistorarchitektur dar, die mithilfe eines vertikalen Transistorkanals einige der vorgenannten Nachteile überwindet. Dadurch ist die Kanallänge deutlich kleiner, als das bei lateralen organischen Transistorbauteilen der Fall ist. Infolgedessen kann er sich als der bisher schnellste organische Transistor mit einer Transitfrequenz von 40 MHz behaupten und Stromdichten bis in den kA/cm^2 Bereich treiben. Nichtsdestotrotz hat der OPBT bislang keine Anwendungsreife erreicht und wird derzeit nur im Labormaßstab auf starren Glassubstraten hergestellt. Hindernisse sind die geringe Produktionsausbeute, große Leckströme und die unklare Zuverlässigkeit der Bauteile. Diese Arbeit nimmt die eben genannten Herausforderungen in Angriff. Es werden OPBTs auf flexible Polymersubstrate übertragen, sowie eine kontrollierte und einfach reproduzierbare Herstellungsmethode für das wichtige Basisoxid durch elektrochemische Anodisierung eingeführt. Die Anodisierungsmethode lässt definierte Isolationsschichten entstehen, was zu stark reduzierten Leckströmen und folglich zu sehr großen Transmissionsfaktoren von 99,9996% führt. Die Untersuchung der elektrischen Stabilität von OPBTs zeigt, dass die Bauteile als Schalttransistoren in organischen Aktiv-Matrix-Displays geeignet sind. Für diese Anwendung sind die Stärken von OPBTs besonders relevant, weil kurze Schaltzeiten und hohe Stromdichten benötigt werden. Mit der vorliegenden Arbeit wird eine Reihe von Meilensteinen auf dem Weg zur kommerziellen Anwendbarkeit von OPBTs erreicht. Damit ist das Bauteil reif für die großtechnische Produktion und die Integration in flexible elektronische Schaltkreise, die die biegsamen organischen Displays der Zukunft ansteuern werden.:1 Introduction 2 Fundamentals 3 Experimental 4 Results – Flexible Devices 5 Results – Anodization of the Base Layer 6 Results – TEM Investigations 7 Results – Electrical Stress Measurements 8 Conclusion and Outlook

Investiga-se a influência de diferentes tratamentos sobre o sistema alumínio com cobertura de óxido de alumínio. A anodização do alumínio em meio de ácido sulfúrico e meio misto de sulfúrico e fosfórico foi empregada para alterar a resistência à corrosão, a espessura, o grau de cobertura e a microdureza do óxido anódico; e a eletrodeposição de ferro no interior óxido anódico em meio de sulfato com tratamento químico de selagem com cério, para alterar a sua condutividade elétrica e a sua resistência à corrosão. Para a eletrodeposição de ferro aplicou-se corrente contínua e pulsada e diversificou-se a composição do eletrólito de Fe(SO4)2(NH4)2.6H2O, com a adição dos ácidos bórico e ascórbico e para o tratamento de selagem, variou-se a concentração do CeCl3. A espectroscopia de energia dispersiva de raios X (EDS), a fluorescência de raios X (FRX) e a análise morfológica por microscopia eletrônica de varredura (MEV) permitiram verificar que, a corrente pulsada eleva o teor de ferro na camada anódica e a presença dos aditivos inibe a oxidação do ferro. As curvas cronopotenciométricas obtidas durante a eletrodeposição de ferro indicaram que a mistura dos ácidos bórico e ascórbico aumentaram a eficiência do processo de eletrodeposição. A espectroscopia de impedância eletroquímica (EIE), medidas de microdureza Vickers (H) e análise morfológica evidenciaram que o tratamento de selagem melhora a resistência à corrosão do filme óxido modificado com ferro. As medidas de impedância elétrica por duas pontas permitiram comprovar o aumento da condutividade elétrica do alumínio anodizado com ferro, mesmo após o tratamento com baixas concentrações de cério. Nanofios de ferro foram preparados utilizando os poros do óxido anódico como matriz. / The influence of different treatments on the aluminum system covered with aluminum oxide is investigated. The aluminum anodization in sulphuric media and in mixed sulphuric and phosphoric media was used to alter the corrosion resistance, thickness, coverage degree and microhardness of the anodic oxide. Iron electrodeposition inside the anodic oxide was used to change its electric conductivity and corrosion resistance. Direct and pulsed current were used for iron electrodeposition and the Fe(SO4)2(NH4)2.6H2O electrolyte composition was changed with the addition of boric and ascorbic acids. To the sealing treatment the CeCl3 composition was varied. The energy dispersive x-ray (EDS), the x-ray fluorescence spectroscopy (FRX) and the morphologic analysis by scanning electronic microscopy (SEM) allowed to verify that, the pulsed current increase the iron content inside the anodic layer and that the use of the additives inhibits the iron oxidation. The chronopotentiometric curves obtained during iron electrodeposition indicated that the boric and ascorbic acids mixture increased the electrodeposition process efficiency. The electrochemical impedance spectroscopy (EIE), the Vickers (H) microhardness measurements and morphologic analysis evidenced that the sealing treatment improves the corrosion resistance of the anodic film modified with iron. The electrical impedance (EI) technique allowed to prove the electric conductivity increase of the anodized aluminum with iron electrodeposited even after the cerium low concentration treatment. Iron nanowires were prepared by using the anodic oxide pores as template.

Investiga-se a influência de diferentes tratamentos sobre o sistema alumínio com cobertura de óxido de alumínio. A anodização do alumínio em meio de ácido sulfúrico e meio misto de sulfúrico e fosfórico foi empregada para alterar a resistência à corrosão, a espessura, o grau de cobertura e a microdureza do óxido anódico; e a eletrodeposição de ferro no interior óxido anódico em meio de sulfato com tratamento químico de selagem com cério, para alterar a sua condutividade elétrica e a sua resistência à corrosão. Para a eletrodeposição de ferro aplicou-se corrente contínua e pulsada e diversificou-se a composição do eletrólito de Fe(SO4)2(NH4)2.6H2O, com a adição dos ácidos bórico e ascórbico e para o tratamento de selagem, variou-se a concentração do CeCl3. A espectroscopia de energia dispersiva de raios X (EDS), a fluorescência de raios X (FRX) e a análise morfológica por microscopia eletrônica de varredura (MEV) permitiram verificar que, a corrente pulsada eleva o teor de ferro na camada anódica e a presença dos aditivos inibe a oxidação do ferro. As curvas cronopotenciométricas obtidas durante a eletrodeposição de ferro indicaram que a mistura dos ácidos bórico e ascórbico aumentaram a eficiência do processo de eletrodeposição. A espectroscopia de impedância eletroquímica (EIE), medidas de microdureza Vickers (H) e análise morfológica evidenciaram que o tratamento de selagem melhora a resistência à corrosão do filme óxido modificado com ferro. As medidas de impedância elétrica por duas pontas permitiram comprovar o aumento da condutividade elétrica do alumínio anodizado com ferro, mesmo após o tratamento com baixas concentrações de cério. Nanofios de ferro foram preparados utilizando os poros do óxido anódico como matriz. / The influence of different treatments on the aluminum system covered with aluminum oxide is investigated. The aluminum anodization in sulphuric media and in mixed sulphuric and phosphoric media was used to alter the corrosion resistance, thickness, coverage degree and microhardness of the anodic oxide. Iron electrodeposition inside the anodic oxide was used to change its electric conductivity and corrosion resistance. Direct and pulsed current were used for iron electrodeposition and the Fe(SO4)2(NH4)2.6H2O electrolyte composition was changed with the addition of boric and ascorbic acids. To the sealing treatment the CeCl3 composition was varied. The energy dispersive x-ray (EDS), the x-ray fluorescence spectroscopy (FRX) and the morphologic analysis by scanning electronic microscopy (SEM) allowed to verify that, the pulsed current increase the iron content inside the anodic layer and that the use of the additives inhibits the iron oxidation. The chronopotentiometric curves obtained during iron electrodeposition indicated that the boric and ascorbic acids mixture increased the electrodeposition process efficiency. The electrochemical impedance spectroscopy (EIE), the Vickers (H) microhardness measurements and morphologic analysis evidenced that the sealing treatment improves the corrosion resistance of the anodic film modified with iron. The electrical impedance (EI) technique allowed to prove the electric conductivity increase of the anodized aluminum with iron electrodeposited even after the cerium low concentration treatment. Iron nanowires were prepared by using the anodic oxide pores as template.

L’objectif de ce travail est d’utiliser les nanoparticules (NPs) de nanosondes fluorescentes de température en particulier dans les films lubrifiants. Le développement de ces nanosondes nécessite la détermination de leurs sensibilités thermiques afin de pouvoir sélectionner les NPs les plus prometteuses. Pour atteindre cet objectif, nous avons présenté deux méthodes d’élaboration utilisées pour la synthèse des nanostructures à base de SiC-3C, la méthode d’anodisation électrochimique et la méthode d’attaque chimique. Dans le premier cas, les analyses FTIR,RAMAN et MET des NPs finales ont montré que la nature chimique de ces NPs est majoritairement formée de carbone graphitique. L’étude détaillée de la photoluminescence de ces NPs a montré que le processus d’émission dépend de la chimie de surface des NPs, du milieu de dispersion et de sa viscosité, de la concentration des suspensions et de la température du milieu. Pour la deuxième famille de NP de SiC, les analyses cohérentes MET, DLS et PL ont montrées une taille moyenne de 1.8 nm de diamètre avec une dispersion de ±0.5nm. Le rendement quantique externe de ces NPs est de l’ordre de 4%. Les NPs dispersées dans l’éthanol, n’ont pas montré une dépendance à la température exploitable pour notre application. Par contre, les NPs de SiC produites par cette voie, étant donné la distribution en taille resserrée et le rendement quantique « honorable » pour un matériau à gap indirect, sont prometteuses pour des applications comme luminophores en particulier pour la biologie grâce à la non toxicité du SiC. Dans le cas des NPs de Si, nous avons également étudié deux types différents de NPs. Il s’agit de : (i) NPs obtenues par anodisation électrochimique et fonctionnalisées par des groupements alkyls (décène, 1-octadécène). Nous avons mis en évidence pour la première fois une très importante variation de l’énergie d’émission dEg/dT avec la température de type red-shift entre 300 et 400K. Les mesures de(T) conduisent à une sensibilité thermique de 0.75%/°C tout à fait intéressante par rapport aux NPs II-VI. De plus il a été montré que la durée de vie mesurée n’est pas fonction de la concentration. (ii) NPs obtenue par voie humide et fonctionnalisées par le n-butyl. Pour ce type de NPs nous avons mis pour la première fois en évidence un comportement de type blue-shift pour dEg/dT de l’ordre de -0.75 meV/K dans le squalane. Pour ces NPs, la sensibilité thermique pour la durée de vie de 0.2%°C est inférieure à celle des NPs de type (i) mais largement supérieure à celle des NPs de CdSe de 4 nm (0.08%/°C). La quantification de cette la sensibilité à la température par la position du pic d’émission dEg/dT et de la durée de vie nous permet d’envisager la conception de nanosondes de température basée sur les NPs de Si avec comme recommandations l’utilisation de NPs obtenues par anodisation électrochimique et de la durée de vie comme indicateur des variations en température. / The goal of this study is the use of Si and SiC nanoparticles (NPs) as fluorescent temperature nanoprobes particularly in lubricating films. The development of these nanoprobes requires the determination of their thermal sensitivity in order to select the best prospects NPs. To achieve this goal, we presented two preparation methods used for the synthesis of 3C-SiC based nanostructures : (i) anodic etching method and (ii) chemical etching method. In the first case, the FTIR, Raman and TEM analysis of final NPs showed that the chemical nature of these NPs is formed predominantly of graphitic carbon. The detailed photoluminescence study of these NPs showed that the emission process depends on the surface chemistry of the NPs, the dispersion medium and its viscosity, the suspension concentration and temperature of the environment.. In the second case, coherent TEM, DLS and PL analyzes showed an average size of 1.8 nm in diameter with a dispersion of ±0.5 nm. The external quantum efficiency of these NPs is 4%. NPs dispersed in ethanol, did not show an exploitable fluorescence dependence on temperature for our application. On the other hand, 3C-SiC NPs produced by this way, given the narrow size distribution and the reasonably high quantum yield for an indirect bandgap material, are promising for applications such as luminophores in particular in the biology field thanks to nontoxicity of SiC. In the case of Si we studied also two different types of NPs. (i) NPs obtained by anodic etching and functionalized by alkyl groups (decene, octadecene). We have demonstrated for the first time an important red-shift in the emission energy dEg/dT with temperature from 300 to 400K. The PL lifetime measurement(T) lead to a thermal sensitivity of 0.75% /°C very interesting compared to II-VI NPs. Furthermore it has been shown that t is not depending on the concentration. (ii) NPs obtained by wet-chemical process and functionalized with n-butyl. For this type of NPs we have identified for the first time a blue-shift behavior of dEg dT in the order of -0.75 meV/K in squalane. The thermal sensitivity for the PL lifetime of these NPs is 0.2%/°C, which is lower than that of NPs obtained by anodic etching method, but much greater than that of CdSe NPs with 4 nm of diameter (0.08%/°C). Quantification of the temperature sensitivity by the position of emission peak dEg/dT and the PL lifetime dτ/dT allows us to consider the realization of temperature nanoprobes based on Si NPs with recommendations to use Si NPs obtained by anodic etching method and PL lifetime as an indicator of temperature changes.

Le Silicium est le deuxième élément le plus abondant dans la croûte terrestre après l’oxygène. Il est produit par voie métallurgique dans un four à arc électrique, le quartz est réduit en présence de réducteurs (charbon de bois, houille et coke de pétrole). Le silicium métallurgique est principalement utilisé dans la métallurgie comme élément d’alliage, dans la chimie et l’industrie solaire. Le prix du Silicium est fonction de sa pureté. Les travaux de cette thèse se divisent en deux parties l’utilisation du Silicium Métallurgique (99% Si) pour le stockage de l’hydrogène, et la photoluminescence du ferrosilicium (disiliciure de fer) de qualité métallurgique. Des substrats de silicium métallurgique ont été soumis à une anodisation électrochimique dans une solution à base d’acide fluorhydrique. Le silicium poreux nanostructuré obtenu est légèrement différent du silicium poreux issu de substrat de silicium de qualité électronique de même résistivité. L’influence des principaux paramètres sur la génération de l’hydrogène : la porosité, la concentration, le volume et la température ont fait l’objet d’une étude détaillée. Le silicium poreux produit à partir de silicium métallurgique est un matériau de stockage d’hydrogène. Des substrats de disiliciure de fer de qualité métallurgique ont été soumis à une anodisation électrochimique. Le composé obtenu est du disiliciure de fer nanostructuré avec du silicium résiduel, ce produit est recouvert de fluorosilicate de fer hexahydraté qui a la particularité d’être luminescent. Il s’agit à ce jour de la première anodisation du disiliciure de fer, un mécanisme de gravure a été proposé et l’influence des principaux paramètres d’anodisation sur les propriétés de photoluminescence a été évaluée. / Silicon is the second most abundant element in the Earth crust after oxygen. Its use in metallurgy, building and electronic industry requires a huge fabrication level. Depending on the contamination level allowed, the price of this material varies in the orders of magnitude. This thesis focuses on the use of dirtiest metallurgical grade silicon and iron disilicide substrates for hydrogen storage and photoluminescence applications. The initial substrates were subjected to electrochemical etching in hydrofluoric acid-containing solutions. Anodization of metallurgical grade silicon substrate produces nanostructured porous silicon with somewhat shifted parameters (comparing with electronic grade porous silicon with the same resistivity), as it was studied in this thesis in details. It was shown, that metallurgical grade porous silicon can be applied as hydrogen storage material. Hydrogen generation is studied here based on the influences of some technically critical parameters: porosity, alkali concentration, volume and temperature. Electrochemical treatment of metallurgical grade iron disilicide substrates produces luminescent iron fluorosilicate hexahydrate, covering the residual nanostructured iron disilicide/silicon. Here, the influence of anodization parameters on photoluminescent properties is studied. Also, etching mechanism is proposed as for the new material never anodized.

In the current study, we give a report when oxalic acid was used as an electrolyte to synthesize an AAO template with hexagonal pore array. Optimum parameters were observed as 0.4 M of oxalic acid, anodizing voltage of 45 V, temperature of approximately 8 °C and the period of 120 minutes. Atomic force microscope (AFM) and High resolution scanning electron microscope (HRSEM) showed that template has an average pore diameter of 103 nm. Co and MnOx (x = 1,2) nanostructures were selectively deposited in the pores of the template using a novel atomic layer deposition (ALD) technique. The diameter sizes and the array of the nanostructures and the template were corresponding. Energy dispersive xrays (EDX) and X-ray photoelectron spectroscopy (XPS) confirmed the presence of Co and MnOx (x =1,2) on the samples while x-ray diffraction (XRD) provided an indication of their orientations. Magnetic force microscopy as main characterization tool showed the existence of multi-domains on both Co and MnOx (x =1,2) nanostructures.