Tesis: "Anodized Alumina"

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Kassangana, Alain Gabriel Mbengu. "Anodized alumina as a template for nanostructure processing". Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=112572.

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A novel way of producing nanostructures in the past decade has been through the use of an anodized alumina template. This template has dense, self-ordered nanometric pores that grow in the oxide as the aluminum is being anodized. This technique is a fairly new method of processing nanostructures, and much study and research is presently being done to understand the formation mechanisms of the highly ordered pores. Ultra-pure aluminum foil and pure aluminium single crystal plates were anodized to create porous anodized alumina, and using it as a template to electro-deposit Nickel nanostructures. The effects different anodizing parameters have on oxide creation were studied, and the results obtained from studying the effects of substrate purity and texture of the anodized aluminum substrate on the morphology of the alumina template, through the use of X-ray diffraction and scanning electron microscopy.
Nickel nanowires were prepared by DC electrodeposition inside the porous alumina template with a gold-palladium coating serving a conductive base. The nanowires have a diameter of 65 nm, and their length depends on the deposition time. The nanowires can uphold a position perpendicular to the substrate by partially dissolving the alumina template. They also have a tendency to gather together once the template is partially removed.

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2

Šťastná, Eva. "Elektrochemické metody přípravy kovokeramických oxidačně odolných vrstev". Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2016. http://www.nusl.cz/ntk/nusl-254367.

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A process with aim to prepare an oxidically and thermal resistant layer was performed on the samples from clear aluminium (99,99+ %, VÚK čisté kovy, s. r. o.) and on the samples from clear titanium (99,95 % Goodfellow) with a layer from sputtered aluminium (99,99 %, VÚK čisté kovy, s. r. o.), An oxidic layer was prepared on the samples by anodization in the oxalic acid. The layer had fine, hexagonally organized pores with the diameter of 30 nm. During the following processing was the structure prepared for the electrochemical deposition of copper to the pores. The aim of the electrodeposition was preparation of copper nanowires deposited into the pores of the oxidic layer. The process was performed in the solution of copper sulfate and sulfuric acid in water. The controlling parameter of the deposition was voltage which had a very asymmetric period. The period had to be optimized for a successful preparation of the wires. The result of the whole process was structure with oxidic matrix whose most of the pores were filled with copper.

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3

Piskin, Fatih. "Deposition And Testing Of Thin Film Hydrogen Separation Membranes". Master's thesis, METU, 2013. http://etd.lib.metu.edu.tr/upload/12615550/index.pdf.

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Industrial production of hydrogen from the syngas, generated from steam reformation of natural gas or coal gasification, sets conditions for hydrogen separation membranes in terms of operating conditions. An alternative source for hydrogen is a syngas generated by gasification of municipal solid wastes which are likely to set more stringent conditions for the separation membranes. There is therefore, a growing demand for separation membranes with improved permeability and particularly of low cost. Among various alternatives, metallic membranes are particularly attractive due to their high selectivity and permeability for hydrogen, exemplified by palladium (Pd). However, due to high cost of Pd there is still a demand to develop alternative metallic membranes that are of low cost and have improved durability. Efforts have therefore concentrated on either alloying Pd so as to reduce its cost or on alternative membrane compositions of particularly b.c.c. structure. The current study deals with hydrogen separation membranes and aims to develop infrastructure for rapid identification of membrane compositions with improved permeability. The study is made up of three parts
i) development of sputter deposition system that would allow deposition of multiple compositions in a single experiment, ii) development of substrate material that would support the thin film membranes and would allow permeability measurement and iii) development of a set-up to measure the permeability of the thin film membranes. In the present thesis, a sputter deposition system incorporating three targets was successfully constructed. The system as tested with palladium-niobium-titanium (Pd-Nb-Ti) ternary system after necessary adjustment would yield thin films of homogenous thickness (&le
7%) over a sample area of &asymp
150 mm diameter. A total of 21 substrates each in 19 mm diameter arranged in triangular form in the substrate holder could successfully be deposited where composition distributions covered a greater portion of Pd-Nb-Ti ternary phase diagram. The structure of the deposited thin films can successfully be controlled by substrate temperature as well as by the pressure of plasma gas (argon). With the help of these parameters, structural diversity can also be produced beside the compositional variation. As for substrates, two materials were investigated. These were titanium dioxide (TiO2) modified porous stainless steel (PSS) and anodic porous alumina (AAO). TiO2 modified PSS due to its associated surface roughness leads to the deposition of films with defected structure which as a result is not gas tight. AAO produced via anodization of aluminum foil had a regular (40-60 nm) pore structure that provides a suitable surface for thin film depositions which could be defect free. However, AAO is very delicate and fragile which makes it difficult to adapt it as a support material for permeability measurement/hydrogen separation purposes. Finally, a set-up was developed for measurement of hydrogen permeability which is capable of measurement over a wide pressure and temperature conditions, i.e. hydrogen pressures up to 10 bar and temperature as high as 450 °
C. It is recommended that so as to identify compositions with improved permeability, Nb or a similar metal which has extremely high permeability could be used as a support material. This would tolerate the evaluation of the films which are not totally defect free.

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4

Wang, Shuo y 王硕. "Tribological behaviour of anodised alumina nanohoneycombs". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2012. http://hub.hku.hk/bib/B49618131.

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Anodic alumina nanohoneycombs (AAO) have been widely used because of its convenient fabrication and controllable pores’ geometry. A lot of investigations have been conducted to study its physical and chemical properties. However, the mechanical properties, especially tribological properties, of such a popular nanomaterial still remain almost unknown. In this project, a series of scratch experiments were conducted on AAO films fabricated by a two-step anodisation method. The testing system is a G200 Nanoindenter provided by Agilent Corporation. A standard diamond Berkovich tip is used as the scratch tip. A scanning electron microscope was used to image the microstructure of the material deformation after scratching. Strengths of AAO domains with different pore regularities were compared by performing the scratch tests at constant normal loads crossing the boundaries separating these domains. Ramping load tests were carried out to show the effects of the normal load on the deformation and friction of the AAO. Scratch cycles and velocities were also varied to see their influence on friction and wear. The results show that the more ordered AAO structure has higher strength than disordered counterparts under scratch testing. The friction coefficient reduces rapidly on increasing normal load, and an explanation of this unusual behaviour is offered by considering the row-by-row deformation of the AAO structure. In multicycle scratch tests, the friction reaches a maximum at the fourth cycle. A step-like deformation behaviour was observed when the scratch velocity became extremely large, and this is probably due to the dynamic response of the instrument.
published_or_final_version
Mechanical Engineering
Master
Master of Philosophy

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5

Strauss, Jon. "Specular reflectance of anodized 6061-T6 aluminum alloy". Kansas State University, 2012. http://hdl.handle.net/2097/15173.

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Master of Science
Department of Chemical Engineering
John Schlup
This study investigated the specular reflectance properties of 6061-T6 aluminum alloy anodized in accordance with military specification MIL-A-8625 as a function of both etch process time and anodization process potential. Both process parameters affect the specular reflectance characteristics when measured using a 660 nm, collimated diode laser source. The etch process time, when varied between 0.5 to 20 minutes, resulted in a decrease in specular reflectivity with increasing time. The anodization process potential was varied between 10 and 21 volts, with a 15 volt condition producing samples with the greatest specular reflectivity. Between the two parameters, the etch time had the greater effect. Additionally, the dependence of the incident beam angle on specular reflectivity was shown not to have a significant effect when compared to the etch process time and process potential.

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6

Gammie, Shantel. "Process improvement to the anodize line through design of experiments /". Online version of thesis, 1996. http://hdl.handle.net/1850/11948.

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7

Gapin, Andrew Isaac. "Fabrication and applications of nanocomposite structures using anodized aluminum oxide membranes". Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2007. http://wwwlib.umi.com/cr/ucsd/fullcit?p3278448.

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Thesis (Ph. D.)--University of California, San Diego, 2007.
Title from first page of PDF file (viewed November 21, 2007). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (p. 128-137).

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8

Timoteo, J?nior Jos? Fl?vio. "Anodiza??o para obten??o de membranas cer?micas". Universidade Federal do Rio Grande do Norte, 2007. http://repositorio.ufrn.br:8080/jspui/handle/123456789/15530.

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This a study on the achievement of alumina membranes by the method of anodizing. From this method got up a layer of aluminum oxide on the anodic metal, who presented the basic properties necessary for the application as a support for the production and acquisition of nanomaterials, such as porosity nano and resistance to high temperature, and other properties, as resistance to corrosion, and chemical, high ranking of the structure and pore size of the pores. The latter, ranging from 10 to 100nm depended on the electrolyte used, which in this study was the H2SO4. To remove all remaining aluminum, it is a bath of dissolution with HCl and CuCl where the residual aluminum has been withdrawn, and the deep pores were opened after chemical treatment with NaOH. After the dissolution, the membranes were calcined at temperatures of 300, 600 and 900? C, and sintered at temperatures of 1200 and 1300? C to win mechanical strength, porosity and observe the desired crystallization. Then went through analyses of composition through X-ray diffraction and morphology of the microstructure through a scanning electron microscope. The method was effective for obtaining alumine membranes applied in the processes of production of materials in nano
Trata de um estudo sobre a obten??o de membranas de alumina atrav?s do m?todo da anodiza??o. A partir deste m?todo obteve-se uma camada de ?xido an?dico sobre o alum?nio met?lico, que apresentou as propriedades b?sicas necess?rias ? aplica??o como suporte para produ??o e obten??o de nanomateriais, tais como: porosidade nanom?trica e resist?ncia a altas temperaturas, al?m de outras propriedades, como resist?ncia ? corros?o, e qu?mica, alta ordena??o da estrutura dos poros e tamanho dos poros. Este ?ltimo, variando de 10 at? 100nm dependeu do eletr?lito usado, o qual neste estudo foi o H2SO4. Para retirar todo alum?nio restante, procedeu-se um banho de dissolu??o com HCl e CuCl no qual o alum?nio residual foi retirado, e os poros profundos foram abertos ap?s o tratamento qu?mico com NaOH. Ap?s a dissolu??o, as membranas foram calcinadas nas temperaturas de 300, 600 e 900? C, e sinterizadas nas temperaturas de 1200 e 1300? C para ganhar resist?ncia mec?nica, porosidade desejada e observar a cristaliza??o. Em seguida passou por an?lises de composi??o atrav?s da Difra??o de Raios-X e morfologia da microestrutura por meio de um microsc?pio eletr?nico de varredura. O m?todo se mostrou eficiente para obten??o de membranas de alumina aplicadas nos processos de produ??o de materiais em escala nanom?trica

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9

Kennedy, Monroe David Jr. "Low-energy radio-frequency sputtering of copper, anodized aluminum, and Kapton by argon plasma ions". Case Western Reserve University School of Graduate Studies / OhioLINK, 1995. http://rave.ohiolink.edu/etdc/view?acc_num=case1058207091.

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10

García, Pérez Alejandro. "Instalación de una planta moderna de anodizado para perfiles de aluminio". Bachelor's thesis, Universidad Nacional Mayor de San Marcos, 2006. https://hdl.handle.net/20.500.12672/550.

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La apertura de los mercados en el país trajo como consecuencia una caída de precios de los productos de aluminio. Es así que la empresa tienen que optimizar sus procesos, reducir costos en todos los ámbitos, para ser competitivo y tener capacidad de satisfacer las necesidades de los mercados internos y externos. Además tendríamos que sumar las regulaciones legales recientes sobre insumos químicos, productos fiscalizados y residuos sólidos que generan toda actividad industrial, los cuales están clasificados en peligrosos y no peligrosos. Siendo los peligrosos los que más restricciones presentan para su disposición final con un alto costo. El presente trabajo “INSTALACIÓN DE UNA PLANTA MODERNA DE ANODIZADO PARA PERFILES DE ALUMINIO”. Contempla todas las inquietudes para ser una planta moderna con tecnología de punta y eficiente. En los primeros capítulos se describe el aluminio, su obtención los países en el mundo que lo producen, las características del Aluminio, usos, los tratamientos tanto de conformación, homogenización, envejecido y protección como es el anodizado además vemos las diferentes aleaciones que se obtienen según el uso que se le quiera dar entre los que están las aleaciones usadas en la producción de perfiles. Seguidamente se evalúa el potencial del mercado peruano en el consumo de perfiles y la forma como es cubierta. Por producción nacional e importación aquí se presenta una gráfica donde se puede apreciar de donde vienen los perfiles importados. Claro esta que tomamos como fuente la aduana marítima del callao. Para determinar la demanda del los perfiles anodizados se realiza un análisis de los datos de los últimos 13 años tanto importación y producción nacional. Dentro de los perfiles anodizados consideramos los perfiles coloreados de preferencia color negro Una explicación de sobre lo que es el anodizado y estudios sobre los factores que afectan el mismo, Seguido de una formula practica para determinar el espesor de la capa anódica nos da una mayor respaldo teórico. Además un amplio despliegue en la tecnología de anodizado nos proporciona herramientas suficientes en la toma de decisiones para la selección de los equipos sobre anodizado, agitación, refrigeración, control de corriente y electro coloreado, calefacción, sistemas de control de soluciones los métodos se análisis de cada baño, las especificaciones de los insumos para el proceso. Con estas bases se determina las dimensiones de la planta para una capacidad de producción de: 1 465 333.24 m2 ó 2 930.66 TM anuales. Continuando con el proyecto se desarrolla la parte de ingeniería que abarca la planta de anodizado y la planta de tratamiento de aguas residuales. Logrando así que la planta sea integral y cumpla con las normativas vigentes. En la estimación del consumo de energía se utiliza la potencia de los equipos, y en la estimación de agua, insumos químicos, combustible, se ha trabajado con índices de consumo en Kg/TM de perfiles anodizados. La parte de ingeniería económica nos muestra la rentabilidad del proyecto. Para la inversión total de $ 3 558 867,00. A un precio de 2,00 $/m2 tenemos una utilidad de neta de 16.44%, mientras que la rentabilidad del capital aportado por la empresa es de 34.24% En la parte final podemos encontrar la parte de las conclusiones, recomendaciones y seguridad ambiental y ocupacional.
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11

Côté, Marie-Pier. "Thin conductive films sputtered on anodized aluminum substrates for dye-sensitized solar cell fabrication". Thesis, McGill University, 2014. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=121592.

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The possibility of using aluminum as a substrate for dye-sensitized solar cells (DSCs) was studied. In order to do so aluminum coupons were anodized in oxalic acid and sputtered with a conductive thin layer of either titanium, molybdenum or indium-tin oxide (ITO). The titanium-coated substrates were used as anodes or cathodes in DSCs in pair with conductive glass electrodes. In turn the molybdenum and ITO-coated substrates were only used as cathodes. The efficiency of the DSCs and their stability were measured by irradiating them using a solar simulator calibrated to reproduce the irradiation of the sun at the Earth's surface. The maximum values of efficiency measured were 6.4%, 4.5% and 2.1% for titanium, molybdenum and ITO cells respectively. The high resistivity of the ITO sputtered film was found to be responsible for the low efficiency of these DSCs. The degradation of the overall conversion efficiency of titanium-based DSCs was studied over 10 days. It was found that the efficiency decreased with time partly due to the reaction of the electrolyte with the metallic electrode. The evaporation of the volatile electrolyte due to sealant limitations was also found responsible for part of the decrease in the efficiency.
La possibilité d'utiliser l'aluminium comme substrat de cellules solaires à pigments photosensibles (DSCs) a été étudiée lors de ce projet de maîtrise. Pour ce faire des coupons d'aluminium ont d'abord été anodisés dans l'acide oxalique puis de minces films conducteurs de titane, de molybdène ou d'oxyde d'indium-étain (ITO) ont été déposés par pulvérisation cathodique. Les substrats de titane ont été utilisés en tant qu'anodes et en tant que cathodes dans des DSCs en pair avec des électrodes de verre conducteur. Les substrats de molybdène et de ITO quant à eux n'ont été utilisés que comme cathodes. L'efficacité de ces DSCs ainsi que leur résistance ont été mesurées en les irradiant à l'aide d'un simulateur solaire calibré pour reproduire l'irradiation du soleil à la surface de la Terre. L'efficacité maximale mesurée pour les cellules de titane, de molybdène et de ITO était de 6,4%, 4,5% et 2,1% respectivement. Il a été montré que la grande résistivité des films de ITO est responsable pour leur faible efficacité. La dégradation de l'efficacité des cellules à base de titane a été étudiée sur une période de 10 jours. Il a été montré que l'efficacité diminuait avec le temps, entre autre à cause de la réaction de l'électrolyte avec le substrat métallique. Une partie de cette diminution de l'efficacité est aussi attribuée à l'évaporation de l'électrolyte volatile.

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12

Dunn, Darrell Scott. "Characterization and evaluation of anodized commercially pure titanium and titanium-aluminum-vanadium alloy surfaces for systemic antibiotic release". Thesis, The University of Arizona, 1990. http://hdl.handle.net/10150/144641.

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Postoperative infections are one of the most feared complications following orthopedic implant procedures. Bacterial infections occur in approximately 1-2% of the patients who undergo orthopedic implant surgery. Treatment of these infections is typically done by administering antibiotics either locally or systemically. Systemic release of antibiotics from bone cement has been reasonably successful. However, it would also be desirable to develop a method of antibiotic release from porous coated implants designed for osseointegration. The principal objective of this research was to explore the feasibility of using anodizing (electrochemical oxidation) as a surface modification technique to facilitate the attachment of antibiotics to commercially pure titanium (CP Ti) and Ti-6Al-4V orthopedic implant materials. In particular the effect of anodizing conditions on the characteristics of the oxide coating such as thickness, composition and porosity has been investigated. Using microbiological methods, the efficacy of in-vitro attachment of antibiotics to anodized surfaces was determined.

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13

Domenici, Natália Virag [UNESP]. "Preparação e caracterização de óxido de alumínio anodizado sobre substratos transparentes". Universidade Estadual Paulista (UNESP), 2015. http://hdl.handle.net/11449/132578.

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Neste trabalho, é apresentada a preparação de filmes finos de Al2O3 por anodização usando a solução eletrolítica contendo etileno glicol e ácido tartárico. Os filmes de Al2O3 foram crescidos por anodização de filmes de alumínio, depositados previamente por evaporação em vácuo em dois tipos de substratos, vidro e ITO, utilizando corrente constante de 0,63 mA/cm2. Filmes de Al2O3 sobre vidro variando a espessura da camada residual de alumínio, e filmes de Al2O3 com 10 nm de camada residual de alumínio sobre ITO foram obtidos visando possíveis aplicações em dispositivos transparentes. Os filmes foram caracterizados através de medidas de capacitância e perda dielétrica em função da frequencia, microscopia de força atômica (AFM) e transmitância óptica. Os resultados mostram que as constantes dielétricas obtidas para os óxidos estão entre 5,4 e 7,8 e a tan está entre 5,0x10-3 e 1,4x10-2. Os valores de constante dielétrica dependem da rugosidade de superfície do óxido e imagens de AFM mostram que esta depende da rugosidade do alumínio evaporado. A partir dos espectros de transmitância ótica, verificou-se que os óxidos obtidos com uma camada residual de alumínio de 20nm apresentam uma transmitância de 80%
In this work, it is presented the preparation of thin films of Al2O3 by anodization using the electrolyte solution containing ethylene glycol and tartaric acid. The Al2O3 films were grown by anodization of aluminum films previously deposited by vacuum evaporation on two types of substrates, glass and ITO using constant current of 0,63 mA/cm2. Al2O3 films on glass with thickness variation of the residual aluminum layer, and Al2O3 films with 10 nm residual layer of aluminum on ITO were obtained in order to have possible applications in transparent devices. The films were characterized by capacitance measurements and dielectric loss versus frequency, atomic force microscopy (AFM) and optical transmittance. The results show that the dielectric constant obtained for the oxides are between 5.4 and 7-8 and is from 5,10x10-3 and 1,4x10-2. The dielectric constant values depend on the oxide surface roughness and AFM images show that this depends on the roughness of evaporated aluminum. From the optical transmittance spectra, it was found that the oxides obtained with a residual layer of 20 nm of aluminum have a transmittance of 80%

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14

Rong, Zhiyang. "Fabrication and characterization of carbon nanotubes for biomedical applications". Worcester, Mass. : Worcester Polytechnic Institute, 2008. http://www.wpi.edu/Pubs/ETD/Available/etd-082508-150545/.

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15

Goetz, John M. "Investigation of coating cracking and fatigue strength of 7050-T74 aluminum alloy with different anodize coating thicknesses". Connect to this title online, 2005. http://hdl.handle.net/1811/327.

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Thesis (Honors)--Ohio State University, 2005.
Title from first page of PDF file. Document formattted into pages: contains v, 40 p.; also includes graphics. Includes bibliographical references (p. 39-40). Available online via Ohio State University's Knowledge Bank.

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16

Vergara, Sotomayor Abel Fernando. "Influencia de las variables de operación del proceso de anodizado del aluminio sobre el comportamiento anticorrosivo de la película de óxido de aluminio". Universidad Nacional de Ingeniería. Programa Cybertesis PERÚ, 2010. http://cybertesis.uni.edu.pe/uni/2010/vergara_sa/html/index-frames.html.

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Este trabajo de tesis trata de un detallado estudio del proceso de anodizado del aluminio, siguiendo el mismo procedimiento que se realiza a nivel industrial. Se determinó como variables de operación de mayor influencia los siguientes parámetros: concentración de la solución ácida, temperatura y densidad de corriente, manteniendo constante el tiempo de operación, el cual fue de 45 minutos. El objetivo del trabajo es establecer el rango óptimo de estas variables, que permita obtener una película de óxido de aluminio, donde se mantenga su apariencia estética pero también posea una alta resistencia a la corrosión después del proceso de sellado. El proceso de anodizado se realizó usando una solución acuosa de H2SO4. La superficie de las placas de aluminio usadas para el anodizado fueron tratadas químicamente con el fin de eliminar las marcas de la extrusión inherente al proceso de producción de las mismas, y eliminar el óxido de aluminio que se produjo al tener contacto el aluminio con el medio ambiente. Como material de partida, para el experimento, se utilizó una aleación de aluminio denominada Al 6063, que es el mismo material utilizado en la industria peruana para producir perfiles ya sean en forma plana o angular, y sobre la cual se realiza un proceso de anodinado. Los cambios de variables del proceso de anodizado, que se consideraron en este estudio fueron: densidad de corriente (1; 1,5; 2 A/dm 2), temperatura (15; 20; 25ºC) y concentración (10; 15; 20%) de la solución H2SO4. Se estableció la influencia de estas variables y las condiciones más adecuadas para la formación de la película de óxido de aluminio poroso que presentó la mayor resistencia a la corrosión, luego que las películas de óxido de aluminio fueron selladas durante 30 minutos. Para determinar el efecto sobre esta resistencia se utilizó el ensayo de Impedancia Electroquímica
This thesis is a detailed study of the aluminum anodizing process, following the same procedure done on an industrial scale. The variables were identified as the most influential in the operation with the following parameters: concentration of the acid solution, temperature and current density at constant time operation, which was of 45 minutes. The study aims to establish the optimum range to obtain a film of aluminum oxide, which retains its aesthetic appeal but also possesses a high corrosion resistance after sealing process. The anodizing process was performed using an aqueous solution of H2SO4. The surface of the aluminum plates were used for anodizing the chemically treated to remove the marks of the extrusion process inherent in producing them. The removal of the aluminum oxide is produced by contact with the medium aluminum environment. As starting material for the experiment, we used an aluminum alloy called Al 6063, which is the same material used in the Peruvian industry to produce profiles in Esther flat or angular, and which performs a process of anodizing. The changes in the anodizing process variables that were considered in this study were: current density (1; 1,5; 2 A/dm 2), temperature (15; 20; 25ºC) and concentration (10; 15; 20%) of the H2SO4 solution. Having established the influence of these variables and which were the most suitable for film formation of porous aluminum oxide with the greatest resistance to corrosion, then the aluminum oxide films were sealed for 30 minutes. To determine the effect on this resistance the Electrochemical Impedance Test was used

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17

Poduri, Shripriya Darshini. "THEORETICAL MODELING AND ANALYSIS OF AMMONIA GAS SENSING PROPERTIES OF VERTICALLY ALIGNED MULTIWALLED CARBON NANOTUBE RESISTIVE SENSORS AND ENHANCING THEIR SENSITIVITY". UKnowledge, 2010. http://uknowledge.uky.edu/gradschool_theses/51.

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Vertically aligned Multiwalled Carbon Nanotubes (MWCNTs) were grown in the pores of Anodized Aluminum Oxide (AAO) templates and investigated for resistive sensor applications. High Sensitivity of 23% to low concentration (100 ppm) of ammonia was observed. An equivalent circuit model was developed to understand the current flow path in the resistive sensor. This helped us in achieving high sensitivities through amorphous carbon (a-C) layer thickness tailoring by employing post-growth processing techniques like plasma etching. A simulation model in MATLAB was developed to calculate the device resistance and the change in the sensitivity as a function of device parameters. The steady state response and transient response of the model to the number of ammonia molecules and its adsorption rate were studied. Effects of oxygen plasma, argon plasma and water plasma etch on thinning of the a-C layer were studied. In order to enhance the sensitivity, the top and bottom a-C layers were replaced by a more conductive metal layer. This also helped in understanding the current flow in the device and in the estimation of the resistivity of the a-C layer.

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Roquete, Ana Paula Jardim. "Avaliação das propriedades capacitivas de recobrimentos de sol-gel aplicados sobre alumínio anodizado". Universidade Federal do Pampa, 2015. http://dspace.unipampa.edu.br:8080/xmlui/handle/riu/1454.

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O desenvolvimento da indústria de eletrônicos junto à miniaturização dos seus dispositivos gera uma demanda de novos sistemas de armazenamento de energia, como os capacitores. Na busca por esses novos sistemas, o estudo de materiais para uso como capacitores tem papel fundamental. O presente trabalho tem por objetivo o desenvolvimento de um recobrimento com propriedades capacitivas em liga de alumínio, tendo como pré-tratamento o processo de anodização, o qual devido à rugosidade formada sobre a amostra pode auxiliar na aderência do recobrimento. Os recobrimentos foram produzidos a partir do processo sol-gel, o qual forma recobrimentos finos de forma consideravelmente simples e econômica. As amostras de alumínio, obtidas de latas de refrigerante, foram lixadas, para a retirada de seus recobrimentos interno e externo, após passaram por um tratamento superficial, por meio do processo de anodização, o qual foi realizado em três diferentes tempos (15, 20 e 30 minutos). Este tratamento superficial foi avaliado pela técnica de Polarização Potenciostática (PP), indicando as melhores condições de anodização para a deposição de sol-gel. A capacitância para este tratamento superficial foi avaliada por meio de Espectroscopia de Impedância Eletroquímica (EIE) ao longo de um período de seis dias em solução de NaCl 3% p/v em pH 2,7. Ambas as análises identificaram a anodização de 15 min como a melhor condição para a realização do tratamento. Amostras com e sem anodização foram então recobertas por oito composições diferentes de sol-gel, e a partir das avaliações de capacitância de cada recobrimento por EIE foi determinada a melhor composição para a adição de um novo óxido, o óxido de rutênio (RuO2), com o objetivo de aumentar a capacitância do recobrimento. As amostras com a última composição foram avaliadas por EIE, determinando a capacitância do recobrimento, Cronocoulometria, para identificação do comportamento quanto ao carregamento, Difração de Raios-X (DRX) e Microscopia de Força Atômica (MFA), avaliando a superfície das amostras. Obteve-se com as medidas de EIE uma menor capacitância para as amostras recobertas com o último sol-gel em relação às amostras anodizadas, porém por Cronocoulometria foi possível verificar carregamento e descarregamento da superfície, o que indicou um comportamento dielétrico do sol-gel, pois manteve a carga de carregamento após a imposição de um potencial contrário ao aplicado. As análises de DRX e MFA comprovaram a ação da anodização devido à presença de pseudo-boemita e rugosidade da amostra, e a indicação de uma região amorfa para amostras com sol-gel, as quais apresentaram superfícies mais planas.
The development of the electronics industry with the miniaturization of devices creates a demand for new energy storage systems, such as capacitors. In the search for these new systems, the study of materials for use as capacitors has a fundamental role. This work aims at the development of a coating with capacitive properties on aluminum alloy, using as pretreatment the anodizing process, which roughness formed on the sample can assist in coating adhesion. Coatings were produced from the sol-gel process, which forms thin coatings in a simple and economical way. The aluminum samples obtained from soft drinks cans were sanded for the removal of its internal and external coatings after undergone a surface treatment by means of anodizing process, which was conducted at three different times (15, 20, and 30 minutes). This surface treatment was evaluated by the technique of Pontentiostatic Polarization (PP), indicating the best conditions of anodizing process for the deposition of solgel. The capacitance for this surface treatment was assessed using Electrochemical Impedance Spectroscopy (EIS) over a period of six days in 3,0 % NaCl solution at pH 2.7. Both analyzes identified the anodizing 15 min as the best condition for the treatment. Samples with and without anodization were then coated with eight different sol-gel compositions, and from the capacitance ratings of each coating was determined by EIA the best composition for adding a new oxide, ruthenium oxide (RuO2), in order to increase the capacitance of the coating. Samples with this final composition was evaluated by EIA, determining the capacitance of the coating, chronocoulometry, to identify the behavior and loading, X-ray Diffraction (XRD) and Atomic Force Microscopy (AFM) evaluating the sample surface. EIS measurements indicating a smaller capacitance for samples coated with the sol-gel in relation to the anodized samples, however chronocoulometry was verified by loading and unloading surface, which indicated a dielectric behavior of the sol-gel, cause it kept the charging load on the establishment of a potential opposite to that applied. The analysis of XRD and AFM confirmed the anodizing action due to the presence of pseudo-boehmite and roughness of the sample, and the appointment of an amorphous region for samples with sol-gel, which had more flat surfaces.

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19

Desrousseaux, Camille. "Prévention de l'adhésion bactérienne et du développement du biofilm sur les dispositifs médicaux de la perfusion via les surfaces nanostructurées". Thesis, Clermont-Ferrand 1, 2015. http://www.theses.fr/2015CLF1PP03.

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Les infections nosocomiales liées aux dispositifs médicaux, et plus particulièrement ceux de la perfusion, sont un problème majeur dans le milieu hospitalier. Ces infections sont liées à la présence de biofilm. Pour lutter contre le biofilm, les mesures préventives en hygiène ne sont pas suffisantes. Les recherches se dirigent vers la modification des surfaces des matériaux des dispositifs médicaux: ajout de substances biocides, développement de surfaces antiadhésives par voie chimique ou topographique. L’objectif de cette thèse est de créer des polymères nanostructurés pouvant entrer dans la composition de dispositifs médicaux de la perfusion et de tester leur impact sur l’adhésion bactérienne et le développement du biofilm. Dans un premier temps, la technique de nanostructuration choisie repose sur la réplication d’un moule nanostructuré en alumine nanoporeuse qui se caractérise par des nanopores auto-organisés en nid d’abeille. Après avoir mis en place une station d’anodisation permettant la nanostructuration de ce moule, la reproductibilité du procédé de fabrication a été validée (diamètre des pores : 51 ± 6 nm, profondeur: 97 ± 9 nm, espace interpores: 102 ± 6 nm). Ensuite, les travaux de réplication ont été effectués avec le polymère ABS (acrylonitrile-butadiène-styrène). Plusieurs méthodes de réplication ont été testées à partir de dépôt de solutions de polymères ou de fonte du matériau sur le moule d’alumine. La méthode sélectionnée sur des critères de reproductibilité et de facilité de transposition industrielle donne des nanostructures de type nanopicots (diamètres des picots : 56 ± 7 nm, distances interpicots : 101 ± 16 nm, longueurs : 73 ± 33 nm). Les surfaces développées sont ensuite caractérisées (MEB, DSC analyse calorimétrique différentielle, spectrométrie Infra Rouge, angle de contact). La fabrication des nanostructures ne semble pas dégrader le matériau ABS et la modification topographique rend la surface plus hydrophile. Une étude de stabilité montre que les nanostructures résistent à plusieurs modes de stérilisation (oxyde d’éthylène, plasma H2O2 et rayon Beta) et sont conservés dans le temps, ce qui les rend applicables à la surface d’un dispositif médical. La seconde étape du travail consiste à évaluer l’adhésion bactérienne sur les surfaces témoins et nanostructurées. Différents tests de culture de biofilm ont été réalisés avec S. epidermidis en conditions statique ou dynamique. Après un temps de 3 à 48h, les bactéries sont décrochées de la surface puis dénombrées sur gélose. Il n’y a pas de différence significative d’adhésion bactérienne entre les deux types de surface. L’observation en microscopie électronique à balayage et confocale à 24h semble confirmer ce résultat. Des tests réalisés avec d’autres souches bactériennes (S. aureus, K. pneumoniae, P. aeruginosa) en condition statique montrent également que l’adhésion est également identique sur les deux surfaces. Par conséquent, nous pouvons conclure que nos surfaces ABS développées avec ces nanopicots spécifiques n’ont pas un effet anti-adhésion sur les bactéries testées. Des recherches récentes mettent en évidence que l’espacement entre les nanopciots est un facteur critique sur l’adhésion bactérienne. L’étape suivante de notre travail consiste à tester de nouvelles nanostructures réalisées avec un moule AAO ayant une distance interpore plus grande
Medical device-related infections are a public health concern and an economic burden. The role of biofilms in medical device-related infections is clearly established. Preventive hygiene measures are not often sufficient to prevent biofilms formation. One promising way of preventing device-related infections is the development of medical devices with surfaces or materials that reduce either microbial viability using biocidal substances or microbial adhesion with topographical modifications.Developing nanostructured polymeric surfaces, which could have applications in medical devices, and testing their impact on bacterial adhesion and biofilm development were the main goals of this thesis. First of all, the polymer was replicated on an aluminum anodized oxide nanostructured mold (AAO), characterized by highly ordered nanopores. An anodization station was made in order to create molds. Then, the reproducibility of the process fabrication was validated (pore diameter: 51 ± 6 nm, deepness 97 ± 9 nm, interpore espace: 102 ± 6 nm). Several replication techniques with ABS were tested including polymers solutions and melted polymers. The selected method was the one with the most reproducible results pillar diameter: 56 ± 7 nm, interpillar distance: 101 ± 16 nm, length: 73 ± 33 nm) and the most representative of industrial injection processes. The created surfaces were then characterized (MEB, DSC, ATR-FTIR, wettability). The fabrication process does not seem to degrade the ABS material and the topographical change increases the hydrophilicity of the surface. A stability study showed that the nanopillars were resistant to several sterilization processes (ethylene oxide, H2O2 plasma, Beta irradiation) and were maintained through time, which is an important element for applications in medical-devices.The second step of our work consisted of assessing bacterial adhesion on control and nanostructured ABS samples. Several biofilm tests were made with S. epidermis in static and dynamic conditions. Between 3 and 48 hours of culture, bacteria were removed from the surfaces and then viable plate counting was performed. No significant differences were observed between the samples. Microscopic observations (MEB, CSLM) seemed to confirm this result. Other bacteria with different morphologies were tested (S. aureus, K. pneumoniae, P. aeruginosa): bacterial adhesion was similar for the two surfaces. Therefore, we can conclude that our developed ABS surfaces with these specific nanopillars do not have an anti-adhesion effect on the tested bacteria. Recent researches showed that spacing between nanopillars is a critical factor on bacterial adhesion. The following step of our work would be to test new nanostructures using AAO molds with bigger interpore distance

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Guastalli, Andrea Raquel. "Estudio sobre la Aplicación de la Tecnología de Membranas para la Recuperación del Ácido Fosfórico de las Aguas de Lavado en el Proceso de Anodizado del Aluminio". Doctoral thesis, Universitat de Barcelona, 2006. http://hdl.handle.net/10803/69956.

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La anodización es un proceso electrolítico que convierte la superficie metálica en un recubrimiento de óxido insoluble. El aluminio es el material anodizado con más frecuencia. El llamado “abrillantado” del aluminio se realiza comúnmente con baños de ácido fosfórico concentrado. Después de la anodización, las piezas deben enjuagarse cuidadosamente, y es en ésta operación en la que se produce una dilución de la solución del baño arrastrada en la capa de óxido formada. Es en este aspecto donde se plantea la mejora de la calidad medioambiental del sector mediante un plan de recuperación y reutilización de los ácidos diluidos en las aguas de lavado, especialmente del ácido fosfórico. Las membranas son una herramienta atractiva que ofrece un amplio rango de aplicaciones, especialmente en el campo de la alimentación, bebidas, bioquímica, etc. Hay muchos ejemplos que pueden encontrarse en el tratamiento de efluentes, la desalinización de aguas o la concentración de soluciones. La separación de diferentes componentes se consigue por la acción de una membrana separadora y por la influencia de una fuerza impulsora a ambos lados de la membrana (presión, concentración, campo eléctrico). Son objetivos de este trabajo: Realizar un aporte a la investigación sobre la recuperación de materia prima en efluentes industriales mediante técnicas de membrana El eficaz aprovechamiento de la materia prima mediante el reciclado de los ácidos a los baños de anodizado La reducción del volumen de aguas residuales finales, con la correspondiente reducción en la contaminación ambiental del medio receptor La elaboración de una propuesta técnico-económica innovadora en el sector del recubrimiento metálico Los principales resultados obtenidos son: Se ha encontrado que las membranas de nanofiltración DK de Osmonics y la MPF-34 de Koch permiten una adecuada separación entre el Al3+ y los ácidos fosfórico y sulfúrico de las aguas de lavado. Los rechazos promedio (del ensayo de concentración) de Al3+ y H3PO4 para la membrana MPF-34 son de 99,7% y de 66,9% respectivamente y para la membrana DK de 99,5% y de 32,3% respectivamente. - Se han desarrollado expresiones para poder estimar adecuadamente los rechazos de Al3+, H3PO4 y H2PO4- en función de la composición del alimento con la membrana MPF-34. Se ha visto que estos valores son los intrínsecos de la membrana. Estas expresiones se obtuvieron mediante un estudio fenomenológico debido a que la complejidad del problema no permite hacerlo desde el punto de vista mecanístico. Se ha encontrado que la estabilidad de la membrana DK en el medio ácido del alimento es suficiente para asegurar un funcionamiento adecuado a nivel industrial. Un tratamiento utilizando la membrana DK permite una recuperación del 73% del ácido fosfórico. En el ácido fosfórico recuperado la relación Al/H3PO4 es de 0,11% en peso mientras que en la disolución alimento inicial era de 6%. Se ha visto que las membranas tanto poliméricas como cerámicas con un PMC de 1000 Da o más no permiten una recuperación adecuada del ácido fosfórico, debido a que el máximo rechazo de Al alcanzado ha sido del 58%. Para las condiciones estudiadas y debido a la naturaleza del las disoluciones tratadas la electrodiálisis no permite una recuperación adecuada del ácido fosfórico Se ha visto que la UFAP no permite separar el Al debido a que no es posible formar complejos Al-Polímero en medios ácidos como el del alimento. La adición de especies que permitan variar el pH de las disoluciones complicaría la recuperación del ácido debido a la presencia de impurezas adicionales.
Most of the hazardous waste in a metal finishing operation comes from the wastewater generated by rinsing operations. The acidic solution that is dragged out from the bath into the following rinsing tanks is the primary source of contamination of rinse water. The use of acidic solutions is very common in metal processing. Sulphuric acid, hydrochloric acid, phosphoric acid, chromic acid and nitric acid are used in chemical bath for anodising, galvanising, brightening, plating and pickling process. The known strategies to reduce the pollution in the wastewater effluent are based on the recovery of contaminant compounds to be recycled to the process reducing the expense in fresh compounds. By definition, recycling includes all measures in order to reduce volume of effluent by recovery raw materials from wastewaters. Membrane separation has become a competitive technology to traditional water treatment processes because of highly effective in removing most inorganic and organic contents to produce a very pure effluent.

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Appusamy, Boopathy Harish y Pavan Kumar Bonthala. "Electrochemical etching and anodizing as key stages of surface treatment of aluminium foil for electrolytic capacitor industry : Application of Electro Chemical Impedance Spectroscopy as non-destructive characterization of etched anode foil with an anodized dielectric oxide layer". Thesis, Tekniska Högskolan, Högskolan i Jönköping, JTH, Produktutveckling, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-37858.

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In the initial stage, the sample preparation was done by using the techniques of Anodic etching and anodic forming processes where a repeated trial and error method of sample preparation headed towards making out a suitable sample set for characterization. After this step, the set of 2 different industrial samples were introduced and anodic oxide forming process was carried out in different electrolytes. In the sample preparations, 4 different electrolytes were used 15% wt. Ammonium Adiphate, 1.5% wt. Ammonium Phosphate, 7% wt. Boric acid and 15% Penta Borate at different stages for performing the anodic oxide forming process. Minimum forming voltages of 20V to a maximum of 100V was employed in the sample preparation and to overcome the waiting time in forming the etched samples a higher current of 0.5A was used. After the samples preparation, Electrochemical Impedance spectroscopy was used as a tool for characterising the various groups of samples and for observing the micro structures of various samples, they were fractured and the observed on the cross section by SEM. After the analysis of the etched samples was made, an attempt to compare the results of the data of these samples to that of the 2 set of industrial samples was made and found that the resultant data wasn’t stable enough to characterize since huge scattering were occurring and whereby the simulation of the CPE circuit for the chosen circuit in the analysis was not possible. Under the analysis, a randomly chosen industrial sample was also used and the resultant data was utilised in understanding the response of the system to different electrolytes.
Sammanfattning Avhandlingsarbetet har genomförts på KEMET AB i samarbete med yttekniklaboratoriet vid JTH i syfte att karakterisera den etsade anodiska aluminiumfolien som grundprov med anodisering och etsning för ytbehandling. I inledningsskedet gjordes provberedningen med användning av teknikerna för anodisk etsning och anodbildande processer där en upprepad provnings- och felmetod för provberedning ledde ut mot att utarbeta en lämplig provuppsättning med avseende på karakterisering. Efter detta steg infördes uppsättningen av 2 olika industriella prover och anodoxidbildande process utfördes i olika elektrolyter. I provpreparaten användes 4 olika elektrolyter 15 % vikt Ammoniumadiphat, 1,5 vikt% Ammoniumfosfat, 7 vikt% Borsyra och 15 % Penta-borat vid olika steg för utförande av anodoxidbildningsförfarandet. Minimala formningsspänningar på 20V till ett maximum av 100V användes i provframställningen och för att övervinna väntetiden vid bildning av de etsade proven användes en högre ström av 0,5A. Efter provberedningen användes elektrokemisk impedansspektroskopi som ett verktyg för att karakterisera de olika grupperna av prover och för att observera mikrostrukturerna i olika prover, de bröts och de observerades i tvärsnittet av SEM. Efter att analysen av de etsade proverna gjordes ett försök att jämföra resultaten av data från dessa prover till den för de två uppsättningarna av industriella prover. Det är konstaterat att de resulterande data inte var stabila nog att karakterisera eftersom stor spridning inträffade och varigenom simuleringen av CPE-kretsen för den valda kretsen i analysen inte var möjlig. Under analysen användes också ett slumpmässigt valt industriellt prov och de resulterande data användes för att förstå systemets respons till olika elektrolyter.

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Chen, Chi-Liang y 陳麒良. "Fabrication of Pt/Sn core-shell electrodes assisted by anodized alumina templates". Thesis, 2011. http://ndltd.ncl.edu.tw/handle/28221840854840362445.

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碩士
國立聯合大學
材料科學工程學系碩士班
99
In this work, the Sn metal, with its high surface energy, is deposited on anodizing aluminum oxide (AAO) templates by physical vapor deposition (PVD) technique. Owing to a comparably low surface energy and the nanoscale roughness of AAO, the Sn metals deposited on AAO exhibit a spherical shape, leading to a structure with high specific surface area. The Pt metal is then deposited on the surface of Sn nanospheres, forming a core-shell structure. The Sn nanospheres are deposited by sputtering on AAO templates anodized by various electrolytes and pore widening process. The X-ray diffraction patterns show that the Sn nanospheres exhibit a body-centered-tetragonal structure, whereas AAO templates are amorphous. The growth of Sn nanospheres deposited by sputtering is dependent on the surface roughness and the deposition time. The contact angle between Sn nanospheres and AAO surface increases with the increase of surface roughness. Besides, the coalescence and growth are inhibited by the surface roughness. On the other hand, the diameter of Sn nanospheres increases as the deposition time increases, which assist the coalescence and growth of the Sn nanospheres. Sn nanospheres deposited by evaporation also show the same trend. The diameter of Sn nanospheres deposited by evaporation increases more rapidly that that deposited by sputtering. The thickness of the Pt coating determined by angle-resolved X-ray photoelectron spectroscopy is about 2.7 nm, equivalent to a Pt loading of 5.79 mg/cm2. As a result, the Sn/Pt nanospheres on phosphoric anodized AAO show the largest electrochemical activity area (EAA) of 57.6 m2 Pt/g Pt. In addition, the Sn/Pt nanospheres on oxalic anodized AAO show the EAA of 38.6 m2 Pt/g Pt. Both of the EAA values are larger than that of Sn/Pt nanospheres deposited on Si wafer. The results reveal that Sn/Pt nanospheres on AAO templates show an enhanced EAA. Besides, the core-shell structure provides a low-cost route to reduce the Pt loadings in fuel cells.

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Domingos, Ismael Duarte. "Nickel nanowire synthesis for next-generation transparent conductors". Master's thesis, 2016. http://hdl.handle.net/10362/21757.

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Nowadays, transparent and touch-related interaction are two significant trends in information and communication technologies (ICTs). For this reason new alternatives to indium-tin oxide (ITO) are being developed, with this work focusing on one possible approach, based on nickel nanowire networks. These are interesting because of its characteristic high conductivity derived from the metal properties, while having the advantage of the chosen material existing with a large abundance, with much lower cost than materials like indium or silver. Several methods for producing these structures were studied. Initially by an hydrothermal process that proved necessary to have a good control of the applied magnetic field, allowing to obtain nanowires with diameters of 800nm but with a wide variety of lengths. To assure a better process control another route was explored, based on electrodeposition using a mold, varying the reaction time, the applied current and also the electrolyte concentration. For this mold was firstly used an anodized alumina membrane that revealed to require a good etching process of the contact in the mold for a good separation to occur between this and the final product. This resulted in nanowires with about 200 nm diameter and lengths around 60 μm. Finally, alternative materials were used for molds, such as wax, polydimethilsiloxane (PDMS) and epoxi-based photoresist (SU-8), but all resulted in low aspect ratio structures. This work opens pathways for low cost conductive nanostructures, with applications ranging from transparent conductors to 3D interconnectivity in integrated circuits.

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24

SUN, HSUAN-MIN y 孫萱旻. "Surface Defect Detection For Anodized Aluminum Tube". Thesis, 2016. http://ndltd.ncl.edu.tw/handle/67715433887296619054.

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碩士
國立雲林科技大學
電機工程系
104
In this study of the tubes to be detected for the two types, one is the bicycle shock absorbers used by the shock tube, the other is the printer of the O.P.C. drum. Aluminum tubes have pre-anodized and anodized and as well as glossy and foggy surface. With the growing popularity of cycle racing, the quantity demand of relevant components is also increasing year by year, which accordingly leads to the increase of productivity. Since Taiwan bicycle industry is mainly for export, product quality is the main concern in the manufacturing process. At present the laser printer is the highest-level printer. It can print high-quality images. To print such images, an O.P.C. drum which is clean and has no defect is needed. Therefore, the quality of the O.P.C. drum plays an important role. Currently, the industry is still using human eyes to detect printing, which makes it not easy to meet the needs of industry and is labor-consuming. Moreover, errors occur easily. Therefore, this study is to develop a system which can automatically detect aluminum surface defects by using automated optical inspection (AOI) technology. This system includes a line-scan camera, high brightness linear light source, and a rotating mechanism. In the detection process, the rotating mechanism rotates the aluminum tube, and the vision module captures images. Then, the captured images go through pre-processing, in which complex background and defects are distinguished and removed. After that, the images are analyzed in different ways. This study uses the following four methods to analyze the images: the RFT method, the FFT method, the image subtraction method, and the FFT and image subtraction integration. The result of the study indicates that the four methods have respective process outcomes. Among them, the one with the best defect-detection rate and time-saving process is chosen to be developed. At present, the rate of the image subtraction defect detection is 100%. The processing time, in Halcon, is about 550ms~600ms per tube, while in C#/emgu, it’s about 900ms~1000ms per tube. However, in this study, the company provided only 13 tubes. Preferably, more extensive tests are needed in this system. Hopefully, human-eye detection can be improved or even replaced in the future with the development of an efficient and high-quality defect detection system.

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Chou, IChiang y 周義強. "A Study on Mechanical Property of Aluminum Alloy with Anodized Aluminum Wire". Thesis, 2000. http://ndltd.ncl.edu.tw/handle/71140489271891650416.

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碩士
淡江大學
機械工程學系
88
The present research use the anodizing method to made a uniform anodized layer on the surface of aluminum wire. (One kind of aluminum wire is 1070Al; The diameter of the wire is 0.7mm; The anodized layer is 30μm. Another kind of aluminum wire is 6061Al; The diameter of the wire is 1.2mm; The anodized layer is 22μm.) Using the gravity casting method to make the wire combine with the aluminum matrix. By the manufacturing process, we have made 6061Al/1070 anodized aluminum wire composite and A356.2Al/6061 anodized aluminum wire composite. To discuss the influence of the tensile strength of the anodized aluminum wire resulted from the anodizing process and T6 process. And the influence of the tensile strength of the aluminum alloy with anodized aluminum wire composite resulted from adding the anodized aluminum wire. The results of the experiment indicate: The strengthening factors of 6061 anodized aluminum wire are the results of T6 process and anodizing process. The T6 process has more advances than anodizing process. The strength of 1070 anodized aluminum wire will decrease because of annealing effect. By the morphology of tensile fracture surface we find that the barrier layer’s shear stress result in the covalent debonding of oxidization layer of anodized aluminum wire. The broken of oxidization layer induce the fracture of the aluminum wire. The local necking of 6061 anodized aluminum wire induces the smaller distance between the fractured oxide layers. The diffusive necking of 1070 anodized aluminum wire induces the longer distance between the fractured oxide layers. The tensile strengths of the composites with T6 process and without T6 process are better than the 6061 aluminum matrix and the A356.2 aluminum matrix. The T6 process will induce decrease of elongation of the composites, the 6061 aluminum matrix and the A356.2 aluminum matrix. There is almost no difference of elongation of the composites and its matrix. Because of the 6061 anodized aluminum wire and the A356.2 aluminum matrix have better wetting properties. So this kind of composite material system generated the wetting layer. The existence of the wetting layer impedes the growth of the crack of the aluminum matrix and result in the delay of fracture behavior of composite. The present research has established the tensile fracture mechanism by the tensile strength and the morphology of tensile fracture surface.

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26

Huang, Ying. "Corrosion resistant superhydrophobic nanoparticles-incorporated-anodized-aluminum alloys surfaces". Thèse, 2016. http://constellation.uqac.ca/4051/1/Huang_uqac_0862D_10237.pdf.

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Corrosion on metal surfaces usually leads to severe safety and appearance issues, particularly in automotive applications. Majority of corrosion behaviors occur in a humid environment. Superhydrophobic surface coating significantly reduces contact area between metal surface and liquid due to the non-wetting layer. Therefore, a superhydrophobic surface is valuable to be fabricated in order to prevent corrosion. In this project, superhydrophobic aluminum alloy surfaces were fabricated by electrophoretic deposition (EPD) of stearic acid (SA) functionalized zinc oxide (ZnO) nanoparticle. The deposited thin film shows a water contact angle of ~155°with rolls off properties. The intensity of x-ray diffracted (XRD) peaks of ZnO and hence the thickness of the ZnO films increases with the increase of the bath temperatures. The activation energy of electrophoretic deposition of stearic-acid-functionalized ZnO nanoparticles was calculated to be 0.5 eV from the Arrhenius plot between bath temperature and the XRD peak area. The superhydrophobic SA-functionalized ZnO thin film has a slightly improved corrosion resistance property (polarization resistance of 55 kΩ⋅cm2) as compared with as-received Al alloy (polarization resistance of 50 kΩ⋅cm2). In order to better improve the anti-corrosion property, a modified electrodeposition process was performed to transform the as-received aluminum alloy substrates to superhydrophobic. In the process, the aluminum alloy surface was electrodeposited in the electrolytic solution containing zinc nitrate and stearic acid at 20 V DC. The optimum of molar ratio at (Zn2+/SA) of 0.225 was found to provide a high surface rms roughness of 7.11 ± 0.42 μm and contact angle (CA) of 159 ± 1°. The corrosion resistance of superhydrophobic substrates prepared by electrodeposition was found to be much higher than that of as-received substrate and the superhydrophobic substrates prepared by EPD process. Anodized aluminum has good robust and corrosion resistance properties. Based on the knowledge of electrodeposition process on the as-received aluminum substrate, aluminum alloy was firstly anodized, followed by the electrodeposition process using the electrolyte of zinc nitrate mixing with stearic acid. The formation of low surface energy micro-nanostructured zinc stearate electrodeposition transformed the anodic aluminum oxide (AAO) surface to superhydrophobic, having water contact angle of 160°. The corrosion current densities of the anodized and aluminum alloy surfaces are found to be 200 and 400 nA/cm2, respectively. In comparison, superhydrophobic anodic aluminum oxide (SHAAO) shows a much lower value of 88 nA/cm2. Similarly, the charge transfer resistance, Rct, measured by electrochemical impedance spectroscopy show that the Rct value of SHAAO substrate was found to be 200 times larger than that of as-received aluminum alloy substrate. These results indicate that the superhydrophobic surfaces created on anodized surface remarkably improve the corrosion resistance performance of aluminum alloy. La corrosion sur des métaux peut conduire à des problèmes de sécurité graves dans la vie de tous les jours. La plupart des comportements de corrosion se produisent dans un environnement humide. Les revêtements superhydrophobes, une surface enduites d'une couche non mouillanble, réduit la zone de contact à l’interfacesolide et liquide. Par conséquent, les surfaces superhydrophobes peuvent être fabriquées de manière à éviter que les comportements de corrosion. Dans ce projet, les surfaces en alliage d'aluminium superhydrophobes ont été fabriqués par dépôt électrophorétique (EPD) d'acide stéarique (SA) de nanoparticules d'oxyde de zinc fonctionnalisé (ZnO). Le film mince déposée présente un angle de contact de l'eau de 155°. L'intensité de rayons X diffracté (XRD) des pics de ZnO et, partant, l'épaisseur des films de ZnO augmente avec l'augmentation des températures de bain. L'énergie d'activation de dépôt électrophorétique des nanoparticules de ZnO fonctionnalisé à l’acide stéarique- a été calculée à 0,5 eV à partir du tracé d'Arrhenius entre la température du bain et la surface du pic de XRD. Le film de ZnO superhydrophobe a une petite amélioration de la propriété de résistance à la corrosion (résistance de polarisation 55 k /cm2) par rapport aux telle que reçue alliage Al (résistance de polarisation 50 k/cm2). Afin de mieux améliorer la propriété anticorrosion, un processus d'électrodéposition modifié a été effectuée dans le projet de transformer les substrats en alliage d'aluminium telle que reçue à superhydrophobe. Dans le procédé, la surface en alliage d'aluminium par électrolyse est effectuée dans une solution électrolytique contenant du nitrate de zinc et d'acide stéarique à 20 V DC. La valeur optimale du rapport molaire au (Zn2+ / SA) de 0,225 a été trouvé pour fournir la rugosité de 7,11 ± 0,42 um et l'angle de contact (CA) de 159 ± 1 °. La résistance à la corrosion de substrats superhydrophobes préparées par électrodéposition a été jugée beaucoup plus élevée que celle du substrat telle que reçue et les substrats préparés par un procédé superhydrophobes EPD. Il est bien connu que l'aluminium anodisé a des propriétés mécaniques élevées et résistant à la corrosion. Par conséquent, avec la compréhension du procédé d'électrodéposition sur un substrat d'alliage d'aluminium telle que reçue, l'alliage d'aluminium est tout d'abord anodisée, suivi par le procédé de dépôt électrolytique utilisant l'électrolyte de nitrate de zinc à mélanger avec de l'acide stéarique, qui est le même que sur la telle que reçue surface de l'alliage d'aluminium. La formation d’un film hybride organique-inorganique micro-nanostructuré de stéarate de zinc électrolytique transformé la surface d'oxyde d'aluminium anodique (AAO) à superhydrophobe, ayant angle de 160 ° de contact de l'eau. Les densités de courant de corrosion des surfaces d'aluminium anodisé et d'alliages sont avérés 200 et 400 nA/cm2, respectivement. A titre de comparaison, superhydrophobe anodique d'oxyde d'aluminium (SHAAO) représente une valeur beaucoup plus faible de 88 nA/cm2. De même, la résistance de transfert de charge, Rct, mesurée par spectroscopie d'impédance électrochimique montre que le substrat a été trouvé SHAAO être 200 fois plus grande que le substrat en alliage d'aluminium telle que reçue. Ces résultats ont prouvé que les surfaces superhydrophobes créées sur la surface anodisée ont considérablement amélioré la propriété de résistance à la corrosion de l'alliage d'aluminium.

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27

Chen, Kuan-Hung y 陳冠宏. "Galvanic Corrosion behavior between Anodized Aluminum Alloy and Copper Alloy". Thesis, 2013. http://ndltd.ncl.edu.tw/handle/24718913476084950873.

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碩士
大同大學
材料工程學系(所)
101
The galvanic corrosion behavior of the anodic oxidized AA6061 Al and C1100 Cu couples has been investigated. The anodizing of AA6061-T6 Al plates was controlled to obtain different thickness of 1μm, 5μm and 15μm, respectively. The galvanic corrosion current of the anodized aluminum plate and C1100 copper plate couples was measured by using a zero resistance ammeter in different solution for 8 hours. The control parameters of galvanic corrosion are as following: electrolytes using 3.5wt% NaCl solution and 1.0wt% NaClO solution; temperatures at 25oC, 40oC and 60oC. The results show that AA6061-T6 aluminum plate have the highest galvanic corrosion current, 1200 μA/cm2, among tested specimens under flowing NaClO electrolyte at 60oC. The anodized AA6061-T6 aluminum plates of 15μm anodized layer has the lowest galvanic corrosion current, 15 μA/cm2, in a static 3.5wt% NaCl electrolyte at 25oC. The severe corrosion attack can be observed at the aluminum specimen with thin and non-uniform anodized layer after the galvanic corrosion tests. It is illustrated that the anodizing processing of AA6061 Al plate can effectively reduce the galvanic corrosion of the AA6061 Al and C1100 Cu couples.

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28

Hsueh, Wei-wen y 薛瑋雯. "The research and process on 10nm Anodized Aluminum Oxide channel". Thesis, 2007. http://ndltd.ncl.edu.tw/handle/04003388448080321987.

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碩士
逢甲大學
資訊電機工程碩士在職專班
95
Using AAO technique to control the size of one-dimensional nanomaterials is a successful method by now. Through using AAO, we can grow one-dimensional nanomaterials like Metallic (Fe, Co, Ni) Nanowire array, Semiconductor (CdS, ZnS, ZnO, InP, GaN, GaAs) Nanowire array and Carbon Nanotubes (CNTs). As AAO has the holes with consistent dimension and fixed direction, the size, shape, length width ratio and directionality of Metallic Nanowire array, Semiconductor Nanowire array and CNTs that made from AAO can be precisely controlled. It has many potential applications such as nano-magnetic memories, nanosensors, nanophotonic devices, Nanophotonic FPDs, nano-energe devices and nanoelectronic devices. There are many articles talking about CNTs and nanowires growth from AAO. This study is focusing on the fabrication of AAO with effective channel dimension control.

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29

Tsai, Chi-Ying y 蔡奇穎. "Galvanic Corrosion Behavior between Anodized Aluminum Alloy and Brass Alloy". Thesis, 2014. http://ndltd.ncl.edu.tw/handle/72987323446724040600.

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碩士
大同大學
材料工程學系(所)
102
The galvanic corrosion behavior of anodic AA6061 Al and C2800 brass couples is investigated. Anodized AA6061-T6 Al plates were produced at different thickness of 1μm, 5μm and 12μm, respectively. The galvanic corrosion current of anodized plate and C2800 brass plate couples was measured using a zero resistance ammeter for 8 hours in two solutions, 3.5wt.% NaCl solution and 1.0 wt.% NaClO solution under temperatures of 25℃, 40℃ and 60℃. The results show that the AA6061-T6 aluminum plate without anodizing produced the highest galvanic corrosion current, 600 μA/cm2, among the tested specimens under flowing NaClO electrolyte at 60℃. Anodized AA6061-T6 aluminum plates with a 12μm anodized layer produced the lowest galvanic corrosion current, 0.11 μA/cm2, in a static 1.0wt.% NaClO electrolyte at 25℃. Severe corrosion attack was observed at the aluminum specimen with thin and non-uniform anodized layer after the galvanic corrosion tests. The anodizing AA6061 Al plate process can effectively reduce the galvanic corrosion of the AA6061 Al and C2800 brass couples.

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30

Chao, Tsu-An. "Nanopatterning of Crystalline Silicon Using Anodized Aluminum Oxide Templates for Photovoltaics". Thesis, 2014. http://hdl.handle.net/1807/65544.

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A novel thin film anodized aluminum oxide templating process was developed and applied to make nanopatterns on crystalline silicon to enhance the optical properties of silicon. The thin film anodized aluminum oxide was created to improve the conventional thick aluminum templating method with the aim for potential large scale fabrication. A unique two-step anodizing method was introduced to create high quality nanopatterns and it was demonstrated that this process is superior over the original one-step approach. Optical characterization of the nanopatterned silicon showed up to 10% reduction in reflection in the short wavelength range. Scanning electron microscopy was also used to analyze the nanopatterned surface structure and it was found that interpore spacing and pore density can be tuned by changing the anodizing potential.

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31

Liu, N. W. y 劉乃瑋. "Failure research of anodized aluminum parts used in dry etching chambers". Thesis, 2000. http://ndltd.ncl.edu.tw/handle/76775671413851917949.

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32

Zhou-WeiWang y 汪宙緯. "A study on fabrication and characteristics of porous anodized aluminum oxide from 1050 aluminum alloy". Thesis, 2018. http://ndltd.ncl.edu.tw/handle/27r5ga.

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33

Wei, Zhiyuan. "Template-based Ferromagnetic Nanowires and Nanotubes: Fabrication and Characterization". Thesis, 2013. http://hdl.handle.net/1969.1/149593.

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This dissertation describes experimental studies of the structures and properties, and their correlations in ferromagnetic nanowires and nanotubes fabricated using porous templates. Ferromagnetic Ni and Fe nanowires with diameters 30 ~ 250 nm were electroplated into the pores of anodic aluminum oxide membranes. The effects of nanowire diameter on structural and magnetic properties were investigated. The microstructures of these nanowires were studied using X-ray diffraction and selected-area electron diffraction measurements. The magnetic properties of the nanowires were investigated using magnetic hysteresis measurements and magnetic force microscopy. Additionally, ferromagnetic Ni-P nanotubes were fabricated using an electroless chemical deposition method. Structure and composition analyses were conducted using X-ray diffraction and energy-dispersive spectroscopy. The magnetic properties of the nanotube arrays and the electronic properties of individual nanotubes were studied. Hysteresis measurements revealed that the 250-nm diameter Ni nanowires had a poor squareness in their hysteresis loops, indicating the existence of multi-domain states. In comparison, the squareness in the hysteresis loops of 60-nm and 30-nm Ni nanowires was much improved, suggesting the existence of single domain states in these smaller diameter nanowires. Magnetic force microscopy measurements confirmed the magnetic domain structures suggested by magnetic hysteresis measurements. Similar investigations of Fe nanowires with diameters of 250 nm and 60 nm found that they all have multidomain magnetic structures. This is expected based on their material properties and polycrystalline structures. Furthermore, magnetic structures of Y-branches and multi-wire clusters were also studied using magnetic force microscopy. The as-prepared Ni-P nanotubes had an amorphous structure. Following a heat treatment, however, a structural phase transformation from the amorphous phase to a crystalline phase was observed using X-ray diffraction measurements. The tetragonal crystalline phase of Ni3P and the face-centered-cubic phase of Ni were confirmed via simulations by the GSAS software. The high Ni3P content accounts for the semiconducting behavior and a low magnetic anisotropy observed in the Ni-P nanotubes.

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34

Huang, Yen-Chih y 黃彥誌. "Electrolytes for the Preparation of Pure Aluminum in Anti-corrosion Anodized Surface". Thesis, 2013. http://ndltd.ncl.edu.tw/handle/q5k4w8.

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碩士
國立臺北科技大學
材料及資源工程系研究所
101
This study is the use of salt spray test, the test form a porous alumina specimen corrosion resistance. Experiments using three sets of concentration 1Vol%, 5 Vol% and 10 Vol% phosphoric acid (Phosphoricacid) as anodizing electrolyte solution, first cut good aluminum specimens, respectively, after acetone, alcohol and water in the ultrasonic vibration machine after 10 minutes, the shock, then the specimen is placed an anode, a cathode placed on platinum sheet, with four groups of voltage 110V, 130V, 150V and 170V for 30 minutes, anodized, 0.5M NaOH and then through the oxide film to remove surface irregularities Finally the second anodic treatment for 4 hours the surface will generate a hexagonal honeycomb structure of dense oxide film, a total of 12 groups of test pieces. 12 groups of test pieces and then do SEM, high group count and voltage resistance tester tests, and finally do find out how much salt spray test voltage and the concentration of phosphoric acid solution specimen has the best corrosion resistance. The result is 5Vol% phosphoric acid test piece 150V and 170V, 10Vol% phosphoric acid test strip 150V best corrosion resistance

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35

LEE, CHI-HSIU y 李奇修. "Analysis of 7XXX series aluminum alloy surface defects and anodized optimal conditions". Thesis, 2016. http://ndltd.ncl.edu.tw/handle/r55zk6.

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36

Liu, Lin-Yi y 劉林益. "Improvement of Anodized Aluminum Oxide Process and Application in Solid-state Supercapacitor". Thesis, 2014. http://ndltd.ncl.edu.tw/handle/39654596070529270621.

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碩士
國立臺灣大學
機械工程學研究所
102
Most nanostructures are fabricated using electron beam (E-Beam), reactive ion etching (RIE) with high-energy beam direct write lithography to achieve the production of sub-micron structures. The high cost and long processing time prevent the application of nanostructures in industry. Anodized Aluminum Oxide(AAO) can provide large-area ordered nano-pores at relatively low cost. This study first attempts to improve the process. There are 2 type substrates used. One is aluminum of high purity : 99.999%(5N) and 99.5%(2N). The other is standard aluminum 1050 and 5052 that are used in the industry. Conventional AAO used the same electrolyte for the first and second anodizations. In this study, different electrolytes are used: 0.3M oxalic acid in the first anodization and 0.1M phosphoric acid in the second (and third) anodization . This different solution treatment has better arrangement than the conventional two-step process using the same electrolyte. Furthermore, by using Taguchi method, we optimize the gas-assisted hot embossing process for fabrication of the best nano-pillar on PC films. This nanostructures produced in polycarbonate film (PC film) surface can reduce the reflectivity to 0.99 %. A solid-state supercapacitors using PC film of nanostructures as electrodes for TiO2 nanoparticle was made. The specific capacitance of the supercapacitors with the best nanopillar structures as electrode is 0.148 μF/cm2 ( 0.198 mF/g )﹐while that without nanostructures is 0.0075 μF/cm2 ( 0.00392 mF/g ). This study proves the potential of using AAO nanostructures for enhancing the capacitance of solid-state supercapacitors.

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37

Li, Ming-Da y 李明達. "An Impedance Studies on Pure Aluminum Surface of Heat Treated for its nanosized Anodized Aluminum Oxide(AAO)". Thesis, 2012. http://ndltd.ncl.edu.tw/handle/56dj6h.

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碩士
國立臺北科技大學
材料及資源工程系研究所
100
In this study, the AAO (Anodic Aluminum Oxide) nanotubes formed on the surfaces of Aluminum specimens were characterized by conducting the Electrochemical Impedance Spectrum (EIS) analysis for their structures. The anodization was performed in the cell of 1wt% Phosphoricacid with aluminum anode and platinum cathode. Experiments conditions were set with 150 voltage of applied potential for 30 minutes and used 0.5M NaOH to remove un-regular AAO，and then anodized 4 hours and used 6wt% Phosphoricacid widing for one hour to have an ordered channel-array of (AAO) nanotubes. Surface layer of dense and regular anrrangment of hexagonal honeybomb structre of the oxide film.The morphologies and properties of AAO nanotubes under the different temperature heat treatment were employed by using SEM and XRD. The results showed that the formation of porous aluminum membrane apecimem after annealing 200℃,showed a wide range of generating microorganization and erected on the strcture. The specimen has the largest impedance, the best corrosion resistance.

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38

Rajendra, A. "Pressure Sensor Development Using Hard Anodized Aluminum Diaphragm And Thin Film Strain Gauges". Thesis, 2006. http://hdl.handle.net/2005/344.

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The sensor is a device that converts a form of energy concerning which the information is sought, called the measurand, to a form (electrical) in which it can be usefully processed or interpreted. Sensors rely on physical or chemical phenomena and materials where those phenomena appear to be useful. Those phenomena may concern the material itself or its geometry. Hence, the major innovations in sensors come from new materials, new fabrication techniques or both. Normally, thin film sensors are realized by depositing a sensing film on a suitable substrate. There could be many combination of metals and insulating materials being deposited depending upon the application or sensing requirements. In general, sensors for various applications are fabricated using a variety of liquid phase technologies (also called as wet methods) and gas phase technologies (also called as dry methods) of deposition. Hence sensor fabrication technology requires various combination of processing technologies and newer materials. In the present work, an attempt is made to design and fabricate a thin film based pressure sensor using a combination of wet and dry deposition techniques. The diaphragm, used for sensing the pressure is coated with a hard anodic coating (Al2O3) using a wet technology, viz. pulse hard anodizing technique, for electrical insulation requirement. The piezo-resistive strain sensing films were deposited onto this coating by dry method, namely, DC Magnetron sputtering technique.. Chapter 01 gives a brief overview of sensors, their classification, principles of sensing,characteristics, materials used in the fabrication of sensors like conductors and insulators, the components of a sensor. Chapter 02 gives brief information about various techniques of depositions viz., liquid phase technologies (wet methods) and vapour phase technologies (dry methods) used to fabricate the sensors. Also, information regarding the coating property evaluation and coating characterization techniques is included. The chapter 03 presents a detailed account of work carried out to obtain an electrically insulating layer by the development of pulse hard anodizing process for aluminum alloy diaphragm, necessary process optimization and testing. The details related to the development, fabrication and testing of thin film based pressure sensors using aluminum alloy diaphragm with hard anodic coating are presented in Chapter 04. The thin film strain gauges were deposited using DC magnetron sputtering technique. The information about mask design, deposition process parameters, calibration etc is also included. Chapter 05 provides summary of the work carried out and conclusions. The scope of carrying out further work is also outlined.

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39

Chia-HweiLiu y 劉嘉慧. "A study on fabrication and application of anodized aluminum alloy with varied profiles". Thesis, 2019. http://ndltd.ncl.edu.tw/handle/9582rr.

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40

Yang, Po-Jen y 楊博任. "Preparation of Superhydrophobic Surface on Aluminum Anodized in Sulfuric Acid by Pulse Current". Thesis, 2016. http://ndltd.ncl.edu.tw/handle/74627995076637083455.

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碩士
大同大學
化學工程學系(所)
104
The purpose of this research is to prepare the superhydrophobic surfaces on the aluminum materials by simulating the lotus effect. Bionics is a scientific research by simulate the special property of biology,lotus effect is a kind of bionics, a simulate of the lotus effect follows hydrophobicity and self-cleaning of lotus leaf which are not wetted by liquid. Traditionally, we often used direct current (d.c.) is used to fabricate an anodic film on aluminum for the preparation of superhydrophobic surface. In this experiment , pulse current (p.c.) is used to replace the direct current . A good result was found in some respects by using adquate pulse parameters. Firstly, using the two procedures of anodic oxidation by chemical etching and pulse current to make a rough surface structure on aluminum, then the superhydrophobic self-cleaning surfaces are obtained through the self-assembled procedure using the myristic acid. To compare the contact angle made from direct or pulse current ,the latter is obviously better,achieve 162.36°.By using pulse current,the roughness and hardness are average increased 10μm、40 Hv,respectively. And the corrosion resistance is also better than others.After 360 days,the contact angle from pulse current decreases 13.9%, it is better than the than that from direct current of decreasing 16%.

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41

Ting, Pei-Lun y 丁培倫. "Effect of Extrinsic Ions of Electrolyte on Corrosion Behavior of Anodized Aluminum Alloys". Thesis, 2015. http://ndltd.ncl.edu.tw/handle/54465859721432853920.

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碩士
大同大學
材料工程學系(所)
103
This corrosion behavior of the anodized Al alloys in the electrolytes containing different metal ions has been investigated. Anodized AA6061 aluminum and brass plates C2800 couples will also be studied to evaluate the galvanic corrosion effects. The galvanic corrosion current of anodized plate and C2800 brass plate couples was measured using a zero resistance ammeter for 8 hours in two solutions, 3.5wt% NaCl solution and 1.0 wt% NaClO solution contants 3000ppm of copper sulfate and magnesium sulfate. The anodic oxide film is not uniform, when dense anodic film produced pitting. Redox potential of copper is higher than aluminum, when the aluminum sheet was exposed in the solution including Cu ions; copper ions are reduced oxidation-reduction reaction. Copper metal metal and the aluminum is oxidized into aluminum ion and diffused to the solution. The behavior will accelerate the corrosion. It will make aluminum substrate is depleted and breaking the hole, leading to aluminum failure; Redox potential of Magnesium lower than the oxidation potential, magnesium ions do not react with the aluminum, it does not produce corrosion reaction of aluminum alloy.

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42

Lin, Chia-Mei y 林佳枚. "Effect of heat treatment on the microstructure and electrochemicalcharacteristics of the anodized aluminum oxide". Thesis, 2003. http://ndltd.ncl.edu.tw/handle/09851204309253629199.

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碩士
國立成功大學
材料科學及工程學系碩博士班
91
The influences of heat treatment (before and after) on the microstructure and electrochemical characteristics of the anodizing oxide films formed in 85℃ aqueous ammonium adipate electrolyte were investigated. The morphology, crystal structure, and thickness of the anodized oxide films were analyzed and measured by TEM. Using the thickness and the measuring capacitance by LCR-meter of oxide film could calculate relative dielectric constant of oxide. And the electrochemical impedance spectroscope and I-V behavior of the oxide film could also be determined. Both pre- and post heat treatments at 500℃ could induce the formation of crystalline γ΄-Al2O3 in the outer layer of anodized aluminum oxide and consequently increase the relative dielectric constant of the film. The pre-heat treatment could retard film growth during anodizing and economized the required charge to anodize the oxide. The post heat treatment could transform the amorphous anodized oxide to the crystalline accompanied with defect formation and cause a substantial decrease in the resistance of the oxide layer. The re-anodization could further develop and extend the crystalline oxide, and cause an increase in the relative dielectric constant of the oxide film. Additionally, both the thickness and resistance of the anodized oxide film were increased by employing re-anodization treatment.

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43

Zong-JieTsai y 蔡宗杰. "Fabrication of GaN-Based Light-Emitting Diodes with Anodized Aluminum Oxide-Nanoporous Pattern Structures". Thesis, 2013. http://ndltd.ncl.edu.tw/handle/61325388848135602103.

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碩士
國立成功大學
微電子工程研究所碩博士班
101
In this thesis, in order to enhance the crystalline quality of gallium nitride (GaN)-based light-emitting diodes (LEDs), a nanoporous anodized aluminum oxide (AAO) thin film was used to pattern sapphire substrate, which can effectively improve crystalline quality of GaN epitaxial layer. First, we introduce an AAO thin film grown on a sapphire substrate with a highly-ordered pores arrangement by modulating conditions of anodization. After that, the AAO nanoporous pattern was transferred on a sapphire substrate by inductively coupled plasma (ICP) etching process. And we used this anodized aluminum oxide-nanoporous patterned sapphire substrate (AAO-NPSS) to enhance the crystalline quality of GaN-based LEDs. The material analyses as well as optical and electrical characteristics were also studied and discussed. In the study of nanoporous AAO thin film, the regular AAO thin film is successfully grown on a sapphire substrate. Firstly, a thin aluminum layer was evaporated on a sapphire substrate by a thermal evaporator. Oxalic acid was chosen as the electrolyte. Then, the thin aluminum layer was anodized by applying bias voltage. Finally, parameters of anodization were modulated to improve the quality of AAO thin film. In this study, pore widening time was increased to figure out the problem that pore diameters of AAO were too small. In addition, a two-step anodization approach was applied to improve the regularity of pores arrangement. Lastly, in order to shorten the fabrication time and increase convenience of anodization of the highly-ordered AAO thin film, sodium hydroxide (NaOH) solution was utilized as the removing solution. Because of lattice mismatch and remarkable difference in thermal expansion coefficient between sapphire substrate and GaN, highly compressive stress, which is induced with the decrement of growth temperature, leads to many threading dislocations (TDs) on GaN epitaxial layers. These TDs seriously deteriorate device performance and reliability. Hence, in order to alleviate this problem, the employment of AAO-NPSS is used to reduce strain and dislocation density as well as significantly improve the light extraction efficiency (LEE). In the material analyses, from the comparison of transmission electron microscopy (TEM) images, TDs could be reduced by using an AAO-NPSS. In addition, air voids were also formed between GaN layers and the AAO-NPSS. The formation of air voids could reflect photons emitted from MQW upward to top direction rather than be absorbed by bottom package metal. Photons could experience more opportunities to be extracted outside. Moreover, the blueshift phenomenon could also be observed in Raman spectra analyses which could be attribute to the strain relaxation. Most importantly, the studied device exhibits smaller full width half maximum in X-ray diffraction (XRD) spectrum. This result has once again confirmed that crystalline quality of GaN epitaxial layers could be improved by using an AAO-NPSS. As compared with a conventional LED, at 20 mA, the studied device exhibits 52.8% and 43.3% enhancements of light output power (LOP) and external quantum efficiency (EQE), respectively. Substantially, the reduced leakage current and decreased turn-on voltage are also achieved. Reliability of the studied device could also be improved. Therefore, the studied AAO-NPSS shows the promise to fabricate high-performance GaN-based LEDs.

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44

Felty, Michael John. "Adsorption of Propane on the Magnesium Oxide (100) Surface and Synthesis of Anodized Aluminum Oxide". 2008. http://trace.tennessee.edu/utk_graddiss/515.

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This work is divided into two parts: the adsorption of propane on the magnesium oxide (100) surface and the synthesis of anodized aluminum oxide. The adsorption properties of propane on the MgO (100) surface were investigated using high-resolution volumetric isotherm techniques and a computational study was accomplished using Materials Studio. From the adsorption work, the two-dimensional isothermal compressibility, the isosteric heat of adsorption, the differential enthalpy, and the differential entropy of adsorption can be calculated. Three distinct layers of propane were observed to form on the MgO (100) surface and it was determined that a phase transition occurs at 162 K. The simulation study showed that the propane molecule adsorbs on the surface, centered over magnesium, at a distance of 3.18 Angstroms. The molecule is oriented such that the carbon backbone is parallel to the surface and is rotated so that three hydrogen atoms are close to the surface. The calculated minimum energy of this system is 13.70 kcal/mol. The second part of this study focuses on the synthesis and characterization of well defined, close packed, high aspect ratio cylindrical channels in an aluminum oxide matrix. These materials have been systematically produced using a two-step anodization process that provides the ability to tune the pore diameter (<10 nm to 100 nm) while retaining the long-range hexagonal pattern. The effect of varying the type and concentration of the electrolyte was investigated. The synthesized materials were characterized using a scanning electron microscope, an atomic force microscope, and a high-resolution volumetric isotherm station to obtain adsorption and desorption measurements. It was found that these three techniques compliment each other nicely. The SEM results give a quick overview of the topography of the surface, AFM gives a more complete profile of the surface, and the isotherm measurements provide an overall pore distribution. These materials have the potential to be used in the study of gas storage, quantum confinement, and nanowire growth.

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45

Klampfl, Bernhard F. "A parametric study of sulfuric acid anodized 5657 aluminum alloy coatings for thermal control applications". Thesis, 1998. http://hdl.handle.net/1911/17187.

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The optical response of sulfuric acid anodized 5657 aluminum alloy coatings was determined to be greatly dependent upon trace and alloying element concentration. An improved method for WDS analysis of anodized coatings was developed to preclude processing errors and improve spatial resolution since it was shown that the possibility of contamination and/or coating modification must be considered in the development of sample preparation procedures and electron beam parameters. Measured element concentrations were compared with reflectance data to determine the affect of each on absorptance. Silicon and zinc concentrations were much higher than expected, the source of these elements being the substrate 5657 Al alloy. Both of these elements play a role in absorptance and the glass forming abilities of silicon may also affect the structural characteristics of SAA coatings produced on 5657 Al alloy.

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46

Bo-YuChu y 朱柏宇. "A study on effect of process parameters on the optical properties of anodized aluminum oxide". Thesis, 2015. http://ndltd.ncl.edu.tw/handle/81330919614866281075.

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47

Hsieh, Meng Chen y 謝孟芩. "A Study of the Sealing for Anodize Oxide Film of Aluminum Alloy". Thesis, 2010. http://ndltd.ncl.edu.tw/handle/12911967937589529753.

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碩士
國立中興大學
材料科學與工程學系所
98
The aluminum 2024T3 is anodized by chromium acid, and there is a uniform film of aluminum oxide on its surface. It is a non-crystalline structure by X-ray diffraction analysis. In order to obtain a better corrosion-resistance for the film, the coupons are processed separately by sealing with deionized water at 5, 10, 30, 60 and 120 minutes. The process shows a good film density on its surface. The thickness remains constant, but the process results in an increase of hardness and weight for the film. In addition, conductivity is reduced. The property can make a better protected film. The process produces the best surface at 30 minutes. Separately, add the Si、Cl-、F- in deionized water for 30 minutes. The surface structure shows the films become loose, because they can prevent hydroxide deposition. The weight of the films are reduced, and conductivity is increased, resulting in a corrosion from the outside environment. Finally, the process continues with salt spray for 336 hours. The result shows corrosion-resistance is better when adding deionized water, but is reduced when adding trace elements, especially Cl-.

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48

Yang, Meng-Hsueh y 楊孟學. "Study on the heat transfer performance of gravity heat pipes with anodized aluminum oxide nano-surface". Thesis, 2017. http://ndltd.ncl.edu.tw/handle/39609746805241192814.

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碩士
中原大學
機械工程研究所
105
This thesis is conducted with the study on the heat transfer performance of gravity heat pipes with anodized aluminum oxide nano-surface. The main purpose is to experimentally investigate the influences of aluminum oxide nanotube length and diameter on the temperature distribution, thermal resistance, and dryout phenomenon of gravity heat pipes under different thermal powers input. First, the anodic oxidation method is used to generate anodic aluminum nanotubes on the inner wall-surface of the evaporation section of aluminum gravity heat pipes. Then, nano-surfaces with different nanotube lengths and diameters are obtained by controlling the anodic oxidation time and voltage. Further, the shape of those nanotubes are observed by using the FE-SEM. Finally, these gravity heat pipes are placed in a thermal test system so as to measure the temperature, calculate the thermal resistance, and record the dryout phenomenon. The results show that the increase in the anodic oxidation time could increase the length of an anodized aluminum nanotube under a particular thermal power input. Increasing the nanotube length reduces the temperature change between the evaporation section and condensation section and the thermal resistance; moreover, the dryout phenomenon is delayed. In addition, the increase in the anodic oxidation voltage could increase the nanotube diameter. Increasing the nanotube diameter also reduces the temperature change between the evaporation section and condensation section and the thermal resistance; however, the increase in diameter does not seem to affect the dryout phenomenon. In summary, if the anodic oxidation treatment is applied to the inner wall surface of the evaporation section of a gravity heat pipe, the heat transfer performance could be obviously improved. The heat transfer performance of the gravity heat pipe could further be enhanced by increasing the anodic oxidation time and voltage.

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49

Chen, Wei-Chih y 陳偉智. "Preparation of Superhydrophobic Surface on Aluminum Anodized in Mixed Acid after Pre-immersing in Ammonium Molybdate Acid". Thesis, 2015. http://ndltd.ncl.edu.tw/handle/07112485272733460493.

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碩士
大同大學
化學工程學系(所)
103
This research aims at the investigation of preparing the superhydrophobic surfaces on the aluminum materials by simulating the lotus effect. Bionics is a science research by simulate the special biological nature. Lotus effect is a kind of bionics. Lotus surface has the hydrophobicity and self-cleaning of which are not wetted by liquid. The contact angle of superhydrophobic surface is often decline after a long time. In this experiment , using the surface modifier of ammonium molybdate in a pre-immersing step of aluminum to create a molybdenum oxide film which grew on the aluminum surface, it can make the anodic film grows slowly and steadily to build a more dense and hard oxide film. Besides, in the anodic process, a mixing solution of sulfosalicylic acid and sulfuric acid is used to improve the physical properties of anodic film, such as, corrosion resistance and strength. The contact angle of the superhydrophobic film produced from the process with the pre-immersing and mixed acid is better than the convention method, achieves 158°. And, the hardness increases significantly an average value of 100 ~ 150 Hv. The corrosion resistance is also better than others. After 270 days, the aluminum's contact angle decrease the average 4% preparing with pre-immersing, better than the aluminum's contact angle decrease the average 8% preparing without pre-immersing.

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50

董家豪. "Development of PDMS nano pillar array during the cast molding process using nanoporous anodized aluminum oxide(AAO) mold". Thesis, 2014. http://ndltd.ncl.edu.tw/handle/69859461810458846125.

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碩士
國立中興大學
機械工程學系所
102
This study developed PDMS nano pillar array during the cast molding process by nanoporous anodized aluminum oxide (AAO) mold. The self-assembly structure of anodic aluminum oxide (AAO) has been investigated for two-step anodization of 99.9995% aluminum in 8wt% phosphoric acid solution. Before anodization, the sheet was electropolished at room temperature in a mixture solution of perchloric acid and ethanol (1:4, v/v) to reduce the roughness of the aluminum sheet surface. Phosphoric acid was used for first-step anodizations from 120 to 170V at rate of 0.1V/s. Anodization was conducted with vigorous magnetic stirring in a low constant temperature water baths at 0°C. The first-step AAO was immersed into a combination solution of 3.5wt% phosphoric acid and 2wt% chromic acid to remove the residual aluminum oxide. The morphology of the first-step AAO was investigated by a field-emission scanning electron microscope and was seen the hexagonal honeycomb structure on the aluminum substrate. Second-step anodic oxidation process was performed in phosphoric acid at 140V. The thickness of the oxide layer was controlled by anodization time and the nano holes have a depth about 200nm for 6min. Finally, 0.43M phosphoric acid was used to expand diameter to achieve around 200nm and nanoporous anodized aluminum oxide (AAO) mold was fabricated.

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