Dissertations / Theses on the topic 'Aluminum Anodic oxidation Technique'
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1
Madeleine, Teresa Catherine. "The catalytic activity of anodic oxides on aluminum." Diss., Virginia Polytechnic Institute and State University, 1988. http://hdl.handle.net/10919/51935.
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The dehydration of isopropanol over anodic oxides was studied. The catalytic activity of the anodic oxides prepared in phosphoric, sulfuric, and oxalic acid was compared to the activity of ν-Al₂O₃. The effect of various thermal treatments on the catalytic activity was examined. IR spectroscopy proved useful for the study of the effect of thermal treatment on the acidity of the oxides. X-ray photoelectron spectroscopy (XPS) was employed to examine the oxide surfaces both before and after use as a catalyst.
The acidity of the oxides was studied by various methods and related to the activity of the oxides. The acidity of the oxide surfaces was studied by the adsorption of pH indicators on the oxide surfaces. The adsorption of gaseous bases, ammonia and pyridine, was studied by IR spectroscopy and temperature programmed desorption mass spectrometry. It was thus possible to differentiate between Lewis and Brønsted acid sites and to determine the quantity of the acid sites on the various oxides.Ph. D.
2
Cheng, Chuan, and 程川. "Electro-chemo-mechanics of anodic porous alumina nano-honeycombs: self-ordered growth and actuation." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2013. http://hub.hku.hk/bib/B50899582.
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Self-ordered anodic porous alumina with a nano-honeycomb structure has recently been extensively used as templates for the synthesis of various nanomaterials for diverse applications. However, due to the insufficient knowledge on the combined electro-chemo-mechanical processes, the formation mechanism of self-ordering has been under debate for decades without clear conclusions. Also, fast fabrication of highly self-ordered and mechanically stable anodic porous alumina is still a challenge. Furthermore, the actuation behavior of anodic porous alumina upon external mechanical and electrical triggering in an electrochemical cell has not been exploited.
In this work, firstly, we investigated the self-ordering mechanism by establishing a kinetics model involving the Laplacian electric potential distribution and a continuity equation for current density within the oxide body. Current densities governed by the Cabrera-Mott equation are formed by ion migration within the oxide as well as across the interfaces. The pore channel growth, due to electric-field-assisted reactions, is governed by Faraday’s law. Real-time evolution of pre-patterned pore channel growth was simulated in two-dimensional cases by finite element method. The simulations revealed a parameter domain within which pre-patterned pore channels will continue to grow in a stable manner during the subsequent anodization if the pre-patterns are commensurate with the self-ordered configurations, or these are driven into stable if the pre-patterns do not initially match the self-ordered configurations. This was verified in experimentally observed pore channel growth under the guidance of pre-patterns made by focused-ion-beam milling. Furthermore, the simulations revealed that ionization reaction on (001) oriented Al grain is relatively easier than that on (101) grain, which results in stable and unstable pore channel growth on (001) and (101) Al grains, respectively, both of which were observed from the simulations and experiments.
Secondly, a scheme on quantitative evaluation of self-ordering qualities in anodic porous alumina has been developed, based on which we systematically searched the optimum self-ordering conditions, by varying the key anodization factors, including substrate grain orientation, electrolyte concentration, temperature, voltage, and time. A high acid concentration and high temperature anodization method was found. Compared with conventional methods, the present method can realize fast formation of highly self-ordered, and mechanically stable anodic porous alumina under a continuous range of anodization voltage with tunable interpore distances.
Thirdly, reversible bending was found in anodic porous alumina-Al composites upon cyclic electric actuation, as directly observed by an optical microscope and detected by in situ nanoindentation. The bending is thought to be the result of charge-induced surface stresses in the nanoporous alumina. The results suggest a new type of composite materials for applications as micro-scale actuators to transform electrical energy into mechanical energy. Furthermore, the composite exhibits significant softening during in situ nanoindentation when the estimated maximum stress underneath the indenter is exerted on the metal/oxide interface. Softening was further verified by in situ microindentation. Electron microscopy examination indicated that the softening is due to a combination of high compression stress and electric field acting near the interface, which enhance ionization reaction and cause the interface to move faster into the substrate.published_or_final_version
Mechanical Engineering
Doctoral
Doctor of Philosophy
3
Ng, King-yeung, and 吳競洋. "An investigation of the deformation of anodic aluminium oxide nano-honeycomb during nanoindentation." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B42841240.
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Wang, Shuo, and 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
5
賴慶才 and Hing-choi Lai. "Electrochemical studies of the lithium-aluminium anode in methyl acetate." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1986. http://hub.hku.hk/bib/B31207650.
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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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Thieme, Michael, Christa Blank, de Oliveira Aline Pereira, Hartmut Worch, Ralf Frenzel, Susanne Höhne, Frank Simon, Lewis Hilton G. Pryce, and Aleksandr J. White. "Superhydrophobic Aluminum Surfaces: Preparation Routes, Properties and Artificial Weathering Impact." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2013. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-107085.
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Among the materials that can be treated in order to impart superhydrophobic properties are many originally hydrophilic metals. For this, they must undergo a sequential treatment, including roughening and hydrophobic coating. This contribution presents various preparation routes along with various characterization methods, such as dynamic contact angle (DCA) measurements, scanning electron microscopy (SEM) and spectroscopic techniques (FT–IRRAS, XPS, EIS).
Micro-rough surfaces of pure and alloyed aluminum were generated most easily by using a modifie Sulfuric Acid Anodization under Intensifie conditions (SAAi). This produces a micro-mountain-like oxide morphology with peak-to-valley heights of 2 μm and sub-μm roughness components. Additionally, micro-embossed and micro-blasted surfaces were investigated. These micro-roughened initial states were chemically modifie with a solution of a hydrophobic compound, such as the reactive f uoroalkylsilane PFATES, the reactive alkyl group containing polymer POMA, or the polymer Teflo ® AF. Alternatively, the chemical modificatio was made by a Hot Filament Chemical Vapor Deposition (HFCVD) of a PTFE layer. The latter can form a considerably higher thickness than the wet-deposited coatings, without detrimental leveling effects being observed in comparison with the original micro-rough surface. The inherent and controllable morphology of the PTFE layers represents an important feature. The impacts of a standardized artificia weathering (WTH) on the wetting behavior and the surface-chemical properties were studied and discussed in terms of possible damage mechanisms. A very high stability of the superhydrophobicity was observed for the f uorinated wet-deposited PFATES and Teflo ® AF coatings as well as for some of the PTFE layer variants, all on SAAi-pretreated substrates. Very good results were also obtained for specimens produced by appropriate mechanical roughening and PTFE coating.
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Thieme, Michael, Christa Blank, de Oliveira Aline Pereira, Hartmut Worch, Ralf Frenzel, Susanne Höhne, Frank Simon, Lewis Hilton G. Pryce, and Aleksandr J. White. "Superhydrophobic Aluminum Surfaces: Preparation Routes, Properties and Artificial Weathering Impact." Technische Universität Dresden, 2009. https://tud.qucosa.de/id/qucosa%3A26716.
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Among the materials that can be treated in order to impart superhydrophobic properties are many originally hydrophilic metals. For this, they must undergo a sequential treatment, including roughening and hydrophobic coating. This contribution presents various preparation routes along with various characterization methods, such as dynamic contact angle (DCA) measurements, scanning electron microscopy (SEM) and spectroscopic techniques (FT–IRRAS, XPS, EIS).
Micro-rough surfaces of pure and alloyed aluminum were generated most easily by using a modifie Sulfuric Acid Anodization under Intensifie conditions (SAAi). This produces a micro-mountain-like oxide morphology with peak-to-valley heights of 2 μm and sub-μm roughness components. Additionally, micro-embossed and micro-blasted surfaces were investigated. These micro-roughened initial states were chemically modifie with a solution of a hydrophobic compound, such as the reactive f uoroalkylsilane PFATES, the reactive alkyl group containing polymer POMA, or the polymer Teflo ® AF. Alternatively, the chemical modificatio was made by a Hot Filament Chemical Vapor Deposition (HFCVD) of a PTFE layer. The latter can form a considerably higher thickness than the wet-deposited coatings, without detrimental leveling effects being observed in comparison with the original micro-rough surface. The inherent and controllable morphology of the PTFE layers represents an important feature. The impacts of a standardized artificia weathering (WTH) on the wetting behavior and the surface-chemical properties were studied and discussed in terms of possible damage mechanisms. A very high stability of the superhydrophobicity was observed for the f uorinated wet-deposited PFATES and Teflo ® AF coatings as well as for some of the PTFE layer variants, all on SAAi-pretreated substrates. Very good results were also obtained for specimens produced by appropriate mechanical roughening and PTFE coating.
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Наталіч, Вікторія Вадимівна, Виктория Вадимовна Наталич, Viktoriia Vadymivna Natalich, Вячеслав Іванович Перекрестов, Вячеслав Иванович Перекрестов, Viacheslav Ivanovych Perekrestov, Ганна Сергіївна Корнющенко, Анна Сергеевна Корнющенко, and Hanna Serhiivna Korniushchenko. "Отримання упорядкованої системи наноострівців нікелю за допомогою мембран анодно-окисленого алюмінію." Thesis, Сумський державний університет, 2014. http://essuir.sumdu.edu.ua/handle/123456789/39571.
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Упорядковані масиви наноструктур металів привертають значний науковий інтерес завдяки перспективам їх використання в електроніці, оптоелектроніці, сенсорах, ультратонких моніторах. Тому дуже важливою технологічною задачею є створення універсального методу, який би дозволив отримувати впорядковані наноструктури на поверхні підкладки з можливістю контролювати їх форму, розмір, та відстань
між структурними елементами.
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Сьомкіна, Олена Володимирівна. "Удосконалення електрохімічного осадження функціональних покрить міддю на сплави заліза та алюмінію." Thesis, Національний технічний університет "Харківський політехнічний інститут", 2018. http://repository.kpi.kharkov.ua/handle/KhPI-Press/39104.
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Дисертація на здобуття наукового ступеня кандидата технічних наук за спеціальністю 05.17.03 – технічна електрохімія. – Національний технічний університет "Харківський політехнічний інститут", Харків, 2018 р.
Дисертацію присвячено удосконаленню технологічного процесу нанесення функціональних мідних покриттів на вироби зі сплавів заліза й алюмінію, які використовуються для підвищення електро- та теплопровідності, забезпечення надійності контактних з'єднань, надання поверхні каталітичних властивостей. Досліджено кінетику і механізм відновлення гідроксотартратного комплексу міді. Встановлено, що катодний процес протікає в області змішаної кінетики і ускладнений хімічною стадією дисоціації комплексного іона. Розроблено склад електроліту міднення, що забезпечує осадження покриттів з міцною адгезією до більш електронегативної основи. Отриманий розчин екологічно безпечний та стійкий при тривалій експлуатації. Вивчено вплив параметрів електролізу (температури, густини струму, концентрації компонентів розчину) на морфологію і якість одержуваних покриттів. Встановлено, що для поліпшення зчеплення мідного осаду з виробами зі сплавів алюмінію, необхідно створити на їх поверхні оксидну плівку з розвиненою пористою поверхнею, що задається умовами формування. Виявлено корозійні і електричні характеристики сформованих оксидів. Визначено, що додавання активуючої домішки фторид-іону до електроліту міднення сприяє більш рівномірному розподілу металу по поверхні сплавів.Thesis for the degree of candidate of technical sciences in specialty 05.17.03 – technical electrochemistry. – National Technical University "Kharkov Polytechnic Institute", Kharkiv, 2018. The thesis is devoted to the improvement of the technological process of applying copper coatings to products made of alloys of iron and aluminum, which are intended for electrical purposes. The kinetics and mechanism of the reduction of the copper hydroxotartrate complex are studied. It is found that the cathodic process includes delayed stage of electron transfer and chemical dissociation stage of the complex ion. The composition of the electrolyte for copper deposition has been developed, which ensures the deposition of coatings with good adhesion to the electronegative base. The resulting solution is environmentally safe and stable for long-term use. The effect of electrolysis parameters on the morphology and quality of the coatings was studied. In order to improve the adhesion of the copper deposit to parts made of aluminum alloys, it is necessary to create an oxide film having a developed porous surface, which is specified by the conditions of its formation. The corrosion and electrical characteristics of the oxides formed are revealed. It is determined that the addition of the fluoride ion (as activating impurity to the electrolyte for copper plating) promotes a more even distribution of the metal over the surface of the alloys.
11
Сьомкіна, Олена Володимирівна. "Удосконалення електрохімічного осадження функціональних покрить міддю на сплави заліза та алюмінію." Thesis, Національний технічний університет "Харківський політехнічний інститут", 2018. http://repository.kpi.kharkov.ua/handle/KhPI-Press/39049.
Full textAbstract:
Дисертація на здобуття наукового ступеня кандидата технічних наук за спеціальністю 05.17.03 – технічна електрохімія. – Національний технічний університет "Харківський політехнічний інститут", Харків, 2018 р.
Дисертацію присвячено удосконаленню технологічного процесу нанесення функціональних мідних покриттів на вироби зі сплавів заліза й алюмінію, які використовуються для підвищення електро- та теплопровідності, забезпечення надійності контактних з'єднань, надання поверхні каталітичних властивостей. Досліджено кінетику і механізм відновлення гідроксотартратного комплексу міді. Встановлено, що катодний процес протікає в області змішаної кінетики і ускладнений хімічною стадією дисоціації комплексного іона. Розроблено склад електроліту міднення, що забезпечує осадження покриттів з міцною адгезією до більш електронегативної основи. Отриманий розчин екологічно безпечний та стійкий при тривалій експлуатації. Вивчено вплив параметрів електролізу (температури, густини струму, концентрації компонентів розчину) на морфологію і якість одержуваних покриттів. Встановлено, що для поліпшення зчеплення мідного осаду з виробами зі сплавів алюмінію, необхідно створити на їх поверхні оксидну плівку з розвиненою пористою поверхнею, що задається умовами формування. Виявлено корозійні і електричні характеристики сформованих оксидів. Визначено, що додавання активуючої домішки фторид-іону до електроліту міднення сприяє більш рівномірному розподілу металу по поверхні сплавів.Thesis for the degree of candidate of technical sciences in specialty 05.17.03 – technical electrochemistry. – National Technical University "Kharkov Polytechnic Institute", Kharkiv, 2018. The thesis is devoted to the improvement of the technological process of applying copper coatings to products made of alloys of iron and aluminum, which are intended for electrical purposes. The kinetics and mechanism of the reduction of the copper hydroxotartrate complex are studied. It is found that the cathodic process includes delayed stage of electron transfer and chemical dissociation stage of the complex ion. The composition of the electrolyte for copper deposition has been developed, which ensures the deposition of coatings with good adhesion to the electronegative base. The resulting solution is environmentally safe and stable for long-term use. The effect of electrolysis parameters on the morphology and quality of the coatings was studied. In order to improve the adhesion of the copper deposit to parts made of aluminum alloys, it is necessary to create an oxide film having a developed porous surface, which is specified by the conditions of its formation. The corrosion and electrical characteristics of the oxides formed are revealed. It is determined that the addition of the fluoride ion (as activating impurity to the electrolyte for copper plating) promotes a more even distribution of the metal over the surface of the alloys.
12
tsai, Horng-Dar, and 蔡宏達. "Plasma oxidation and anodic oxidation of aluminum thin films." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/90032933555828805925.
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碩士國立中興大學
材料工程學研究所
93
Abstract In this study, Al thin films were oxidized by plasma oxidation and anodic oxidation. The Al films were deposited on polyethylene terephthalate (PET) and Si wafers by DC magnetron sputtering technique. The intensity of C-O group and surface roughness of PET substrates increased remarkably after O2 plasma surface treatment. Form the results of ASTM D3359 test, Adhesion between the Al films and PET substrates was significantly improved when the PET substrates were pre-treated under 100 ~ 200W RF plasma for 5 ~ 10 min. In case of plasma oxidation, X-ray photoelectron spectroscopy(XPS) results showed that the content of alumina overlayer remained unchanged when Al/PET films were treated under 400W RF 13.56 MHz plasma for 1h at room temperature. The alumina content increased when the Al/Si films were plasma oxidized for 1 ~ 2 h above 250℃. The thickness of alumina layer increased parabolically with time. The calculated activation energy was 18.4 ± 0.4 kJ/mole, which was lower than that of thermal oxidation. Anodic oxidation was conducted in 0.3 M oxalic electrolyte. The films synthesized by potentiostatic mode over a wide electrolytic voltage range of 5 - 40 V for 2 - 40 min at low temperature (5 ~ 15℃) on PET and Si wafers exhibited optical transmittance, amorphous structure and insulating capability. The adhesion between the Al film and PET substrate was improved by plasma treatment of PET substrate. XPS results showed that alumina film appeared at 40 V and duration time of 30 min.
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Shiang-Lin, Tzou, and 鄒祥麟. "THE STUDY OF ANODIC OXIDATION OF ALUMINUM." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/87885518163104215556.
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碩士大同工學院
化學工程研究所
86
The main purpose of this research is to study the properties of the films, obtained by pulse current anodizing of nitric acid / sulfuric acid or boric acid / sulfuric acid, on aluminum in mixed electrolytes. The operating conditions are constant voltage of 20 V, P.C. frequency of 200 Hz, bath temperature from 10 to 40℃, duty cycle from 20 to 80 % and anodizing duration time from 10 to 60 min. In film dissolution test, it is proved that the anodic film indeed contains two layers, and the compositions of film is also changed by the anodizing electrolytes. This above results also be obtained from EDS analysis. When nitric acid or boric acid is added into the electrolyte of 10 wt% sulfuric acid, the film thickness and microhardness can increase greatly, especially with adding amount of modifier. Under the conditions of 10 wt% sulfuric acid, duty cycle of 80%, bath temperature of 20 ℃ and anodizing duration time of 50 minutes, the best results of microhardness and film thickness are 162 Hv and 16 μm, respectively. If 15 g/l nitric acid or 15 g/l boric acid is added under the optimal conditions above, the microhardness and film thickness are 467Hv / 35μm and 481Hv / 27μm, respectively.
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Wen-Lun, Yen, and 顏偉倫. "Anodic oxidation of bulk and thin film aluminum." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/13206896401345524708.
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碩士國立中興大學
材料工程學研究所
93
In this investigation, the porous anodic oxidation aluminum films were prepared by electrochemical method. These films were prepared on the high pure bulk aluminum and aluminum thin film (Al/TiN/Si) by using 40 V DC potentiostatic mode in 0.3 M oxalic acid electrolyte. The characterizations of porous anodic oxidation aluminum films growth on aluminum bulk and thin film aluminum are compared at the same conditions. The chromium-mixed solution was normally used in electro-polish process. Nevertheless, a solution mixed with phosphoric acid and sulfuric acid was employed in this study. A phosphate and sulfate contain porous anodic oxidation aluminum films with 2 μm thickness is found on the bulk aluminum and aluminum thin film through 20 V potentiostatic electro-polished at 40 oC for 1 min and 20 min, respectively. Moreover, if the potentiostatic was 40 V and the anodic oxidation times were 10, 30, 60 and 90 min, the film surface with more roughness and porous was observed. In this case, when the anodic oxidation times were 30, 60 and 90 min, the depth of oxidation films were 7 μm, 10 μm and 12μm, respectively. After 30 min anodic oxidation, the anodic oxidation of thin film aluminum was depleted and the anodic oxidation film was stopped growing. Based on the X-ray photoelectron spectroscopy (XPS) analysis, the thickness of oxidation films of bulk aluminum was about 115 nm and 393 nm while on thin film aluminum was about 126 nm and 415 nm, as the anodic oxidation times were 10 sec and 60 sec, respectively. Furthermore, the relative peak intensity of Al-O and Al defined the reaction rate of anodic oxidation by the depth profile of XPS method. The optimized experimental conditions for the anodic oxidation of aluminum bulk are described as follow. At first, the electro-polish process is done in the mixture solution of phosphoric acid and sulfuric acid for 20 min under 20 V potentiostatic at 40oC. Subsequently, the anodic oxidation is proceeding in the 0.3 M oxalic acid solution, as the potentiostatic 40 V and at room temperature for 60 min. Finally, the smooth surface and order holes of the porous anodic oxidation aluminum films can be obtained via remove the bulk aluminum and barrier layer then enlarge the hole dimension of the films in 6 wt% phosphoric acid solution for 30 min. The average diameter of holes is about 70-80 nm. However, the optimum conditions for anodic oxidation of thin film aluminum are electro-polished for 1 min and anodic oxidation for 10 min under same condition with bulk aluminum. Oxidation film with 60-70 nm average holes diameter and 600 nm thicknesses are obtained after carry out 30 min hole enlargement. In addition, we employ the porous anodic oxidation aluminum template in 0.2 M copper sulfate and 0.1 M boric acid mixture solution and applied -0.1 V DC potentiostatic for 30 min to electroplate the copper into the holes. After removing the aluminum template, straight copper nano-wires array are successfully obtained.
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GUO, WEN-YAO, and 郭文堯. "Study on anodic oxidation and electrolytic coloring of aluminum." Thesis, 1988. http://ndltd.ncl.edu.tw/handle/97565677238105868601.
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Huang, Qiyu. "Patterned anodic oxidation on aluminum thin films by nanoimprint lithography /." 2003. http://wwwlib.umi.com/dissertations/fullcit/3108756.
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Wu, Sheng-Po, and 吳聲波. "Fabrication of Nanoporous Gas Sensors Using Anodic Aluminum Oxidation Process." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/f69n5q.
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碩士國立臺北科技大學
機電整合研究所
98
An integrated technology that anodic aluminum oxide (AAO) method and micro- electromechanical systems (MEMS) were proposed. And tin dioxide (SnO2) was used as gas-sensitive material of the nanoporous gas sensors. Firstly, it made use of AAO to manufacture nanoporous alumina membrane to replace limited optical resolution of traditional optical lithography. Secondary, it utilized a dry etching process steps to make nanoporous alumina membrane as a mask manufacture the formation of porous structure on the silica surface. Finally, its tin dioxide been deposited on the porous silica surface to let the area of gas sensing material increase and enhance the working scope of gas sensors. This study completed a sensor structure. By the gas test verified the porous characteristics of the surface. And the gas-sensitive materials be applied annealing for carbon monoxide testing, concentrations were 300 ppm, 500 ppm and 1000 ppm. It was successfully confirm that the gas sensor had better sensitivity at relatively lower operation temperature.
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Wang, Yan-Jie, and 王彥捷. "Improvement of Corrosion Properties on Aluminum-Sputtered AZ91D Magnesium Alloy by Anodic Aluminum Oxidation." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/21780333622489526446.
Full textAbstract:
碩士國立臺灣科技大學
機械工程系
104
Magnesium and its alloy have been used widely for the living facilities and military defense owing to their excellent physical and mechanical properties, such as low density, high strength, good cast-ability and weld-ability, excellent electrical and thermal conductivity, high dimensional stability, good electromagnetic shielding and high recyclability. However, the poor corrosion resistance of magnesium alloys have limited their engineering applications, especially in acidic environment and salt-water conditions. Two processes were used to improve the corrosion resistance of the magnesium alloys, including sputtering and anodized. Since the aluminum film is more stable than magnesium substrate, the aluminum film can be oxidized to aluminum oxide film, to further improve the corrosion resistance. In this study, the sputtering + anodized were carried out on an AZ91D Mg alloy, and the effects on the corrosion resistance were evaluated. The cross-sectional configuration of film was analyzed by Dual Beam Field Emission Focused Ion Beam (DB-FIB), indicated thickness of anodized oxide films increased with the oxide time. The film surface is characterized by X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) which indicated that the anodized oxide layer was amorphous structure and composed by Al2O3. The results of potentiodynamic polarization show that the sputtering Al film and the anodized oxide layer on the AZ91D alloys performed more positive corrosion potential and lower corrosion current density than the AZ91D substrate, by adopting an anodizing treatment 15 minutes specimen have higher corrosion potential value of -1.359 V and lower corrosion current density value of 0.262 μA/cm2. Similar, according to EIS results, the charge transfer resistance of the anodized specimens were larger than the AZ91D substrate. These results proved that the sputtering Al film with anodizing treatment coated on the AZ91D alloys significantly improved the corrosion resistance property of the AZ91D alloys.
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XIE, SU-XIANG, and 謝蘇祥. "Effects of modifiers on anodic oxidation of aluminum by alternating current." Thesis, 1990. http://ndltd.ncl.edu.tw/handle/56168628837616405274.
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Pin-Shan, Chen, and 陳品杉. "THE STUDY OF ANODIC OXIDATION OF ALUMINUM PRETREATED BY AMMONIUM MOLYBDATE." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/31721699706556950512.
Full textAbstract:
碩士大同工學院
化學工程研究所
86
The main purpose in this study is to find the effects of molybdic oxyhydroxide film on anodic oxide film. The A1100 aluminum sheets are dipped in ammonium molybdate solution at first and then anodized in10wt% sulfuric acid solution by direct current with 20V at 20℃. At last, it is sealed in hot water of about 92~95℃.Longer dipping time, adequately higher dipping temperature, higher concentration of ammonium molybdate and pH value of 3 would be helpful to obtain a good anodic film.From SEM, the pores of film through pre-dipping are closely arranged and regularly distributed. And from the EDS, the molybdenum trioxide is found in the anodic oxide film, that can increase the microhardness of anodic films. The maximum thickness of anodic film without pre-dipping of ammonium molybdate is 22μm, and the thickness of anodic film with pre-dipping is almost the same. But the anodic film through pre-dipping treatment has an optimal microhardness of 601±10(Hv50), which is 62% more than that without pre-dipping condition.
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Hsu, Hsiang-Yi, and 徐向儀. "Study of Sodium Ion Selective Electrode Using Anodic Oxidation Technique." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/18777643907919590047.
Full textAbstract:
碩士華梵大學
電子工程學系碩士班
97
In recent years, pH sensors and biosensors played an important role on the chemical analysis and clinical examination. In this article, the anodic oxidation method was used to produce a pH sensor and a sodium ion selective electrode. The biggest drawback of the traditional voltage sensor was that it needed a standard reference electrode to provide measurement system a stable electric potential, thus causing the problems of not being able to minimize the sensor and produce a disposable sensor. In order to solve the above problem, a differential voltage sensor was proposed in this article. This article conducted the analysis and comparison between the anodic oxidation ITO and the ITO. The anodic oxidation ITO could remarkably lower the initial electric potential of the sensor and increase the stability of sensors. In addition, its hysteresis effect was also superior to the ITO. The sodium ion selective electrode was used to recognize sodium-ion concentration. Its sensitivity was 52.5mV/decade when the concentration was at 1M~10-4M, and its sensitivity was 30mV/decade when the concentration was at 10-4M~10-7M. The lowest limit of concentration could reach 10-7M. The differential-voltage type of sodium ion selective electrode was designed and produced in this thesis. The whole structure was built on the ITO glass substrate in order to substitute for the standard reference electrode. The sensitivity was 58.7mV/decade and 19.2mV/decade corresponding to 1M~10-4M and 10-4M~10-5M concentration, respectively. The measurement results revealed that the differential-voltage sodium ion selective electrode could effectively solve the problem of the traditional electrode that needed a standard reference electrode. In addition, it could effectively produce a minimized and disposable selective electrode.
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chen, Lo chi, and 羅吉成. "The study of anodic oxidation of aluminum pre-electroplated by ammonium molybdate." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/85616001380963234928.
Full textAbstract:
碩士大同大學
化學工程研究所
88
Before the anodizing step, the A1100 aluminum sheets were pre-electroplated by using a direct current in the mixed solution of 0.025 mol/L ammonium molybdate and 0.1 mol/L ammonium fluoride. The pre-electroplating conditions are：electroplating voltage from 5 to 30V, electroplating temperature from 10 to 50℃, and electroplating time from 10 to 70 minutes. Then the pre-electroplated aluminum sheets were anodized under the conditions： 15wt% sulfuric acid, anodizing temperature of 20℃, constant voltage of 20V, and plused current with frequency of 200Hz at 80% duty cycle for 30 minutes anodizing duration time. Finally, the specimens were sealed in the solution of 20g/L nickel fluoride for 20 minutes at room temperature. To study the effects of pre-electroplating conditions on the anodic film. From SEM photos, it can be deduced that the pre-electroplating conditions, the higher voltage of 30V at a temperature of 20℃ and electroplating time of 60 minutes, will make the pores of the anodic oxide film become smaller and distributed closely. And the EDS analytic chart reveals that the molybdenum atom is found in the anodic film, that is one of the reasons to increase the microhardness of the anodic film. From experimental results, it can be shown that the microhardness of the anodic film can be greatly improved by the pre-electroplating process. But the thickness of the anodic film is not affected obviously. Under the conditions of 20℃ electroplating temperature, electroplating voltage of 30V and 60 minutes electroplating time, the maximum anodic film microhardness of 586Hv±10 can be obtained, and the its film thickness is 19μm.
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XIE, WEN-YI, and 謝文毅. "Study on anodic oxidation and electrolytic coloring of aluminum by pulse current." Thesis, 1991. http://ndltd.ncl.edu.tw/handle/44223212377063680849.
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Chou, Yen-Chen, and 周彥丞. "THE RESEARCH OF ANODIC OXIDATION OF ALUMINUM IN MIXED ACIDS OF THREE COMPONENTS." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/76681079880066384087.
Full textAbstract:
碩士大同工學院
化學工程研究所
87
The main purpose of this research is to study the properties of the films obtained by pulse current anodizing on aluminum in three components of mixed acid electrolytes, and compare with the films which obtained from single sulfuric acid or two acids bath. The operating conditions are constant pulse current of 1~5A/dm2 with frequency of 100 Hz and duty cycle of 80 % for anodizing duration time from 20 to 60 min at bath temperature of 20℃. The film thickness is linearly proportional to the anodizing time and current density, and is almost not affected by the addition of acid modifier. Comparing with the film obtained from single sulfuric acid or two acids bath, the film microhardness obtained from three component acids can increase greatly. In film dissolution test, the dissolution rates of anodic oxide films formed in different electrolytes are different, and that obtained in three components of acid bath has a faster dissolution rate. The variation of compositions in the anodic film improving the properties of film can be obtained from EDS analysis. Under single-acid conditions of 15 wt% sulfuric acid, duty cycle of 80%, bath temperature of 20℃, and anodizing duration time of 50 minutes, the maximum film microhardness of 330Hv and thickness of 32μm is obtained at current density of 2A/dm2, and the film microhardness of 389Hv and thickness of 52μm is obtained at 3A/dm2. If 5 g/l nitric acid is added into the 15 wt% sulfuric acid under the above conditions, that changes to 372Hv and 36μm at 2A/dm2. If in the case of 10 g/l nitric acid is used, these are 381Hv and 53μm at 3A/dm2. If the third acid of 10 g/l boric acid is added into the solution of 15 wt% sulfuric acid and 5 g/l nitric acid under the above conditions, the values are promoted to 588Hv and 34μm. And, in the solution of 15 wt% sulfuric acid-10 g/l nitric acid-10 g/l oxalic acid, a film of 580Hv and 54μm is obtained.
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Hsiao, Kai-Yi, and 蕭凱憶. "Fabrication of 3D Microchannel by Gas-Assisted Thermoforming Process and Anodic Aluminum Oxidation." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/37308389446091861295.
Full textAbstract:
碩士國立臺灣大學
機械工程學研究所
101
Microfluidic channel with micro/nanostructures on four walls can change flowing behavior and enhance mixing performance due to apparent fluid slip at hydrophobic walls. Micro/nanostructures, however, cannot easily be patterned on sidewalls by lithography approaches. Hot embossing methods were reported to fabricate micro/nanostructures on channel with aid of PDMS stamp or spin-coated PDMS thin film to prevent nano-structures from damage during forming micro-structures. There are problems in patterning corners due to the elastic recovery of PDMS. In this study, gas-assisted hot embossing and thermoforming processes are employed; nanostructures can be replicated and preserved with gas-pressing technique. Besides, inexpensive anodic aluminum oxide (AAO) sheet is to be used as template for fabricating micro/nanostructures. Through gas-assisted hot embossing and thermoforming processes, PC (polycarbonate) films with micro/nanostructures can be fabricated. After cast into PDMS channel and cover plates, their hydrophobic characteristics are verified. The contact angle of water drop has increased from 119 ° to 140 °. They are to be bonded after plasma treatment. Flow tests are performed to compare the flow rates in microfluidic systems with hydrophobic and plain channels. The flow rate in hydrophobic microchannels has increased 24.8% under the same pressure.
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Yang, Min Jie, and 楊閔傑. "Effects of viscosity-increasers on anodic oxidation of aluminum alloy by pulse current." Thesis, 1995. http://ndltd.ncl.edu.tw/handle/87745811688265995063.
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Lee, Wen-Bin, and 李文斌. "THE STUDY OF ANODIC OXIDATION OF ALUMINUM WITH ADDING AMMONIUM MOLYBDATE IN MIXED ACIDS." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/65947649745241824051.
Full textAbstract:
碩士大同大學
化學工程研究所
90
The main purpose of this research is to study the properties of the films obtained by pulsed current anodizing on aluminum in two kinds different mixed acids containing ammonium molybdate. The operating conditions are constant current density of 1~5A/dm2, duty cycle of 80%, frequency of 100Hz and bath temperature is 20℃ for 20~60min anodizing duration time. The anodic film thickness increases with the increasing current density and anodizing time, however, it decreases with the increasing concentrations of ammonium molybdate. The hardness of anodic films obtained from both mixed acid electrolyte increases when ammonium molybdate is added in the mixed acid. From SEM photos, the adding ammonium molybdate makes the pores of anodic oxide film become smaller and be distributed closely. It’s good for film hardness. Besides, the EDS analytic chart reveals that the molybdenum atom is found in the oxide film, that can be explained why the hardness of the oxide film increases.
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Li, Xian Ling, and 李賢令. "Effects of cold sealing and modifiers on anodic oxidation of aluminum by pulse current." Thesis, 1995. http://ndltd.ncl.edu.tw/handle/36816304832124606803.
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Liu, kun Ming, and 劉坤明. "Fabrication of Roughen Transparent Conductive Layer on Solar Cells by Anodic Aluminum Oxide Technique." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/29695645499267717412.
Full textAbstract:
碩士大葉大學
電機工程學系
98
This thesis is to study the effect of micro-structure on anti-reflection for a transparent conducting layer (TCL). The process to form micro-structure on a TCL is as following. First, an Al film was deposited on TCL by E-beam evaporation. Then, porous alumina membrane pores were formed by anodic oxidation technology. Next, TCL was wet etched to form micro-structure on surface by using porous alumina membrane as mask. The aperture size can be controlled with different anodic oxidation conditions, such as oxidation time, oxidation voltage, barrier layer removal and pore widening time. Both surface morphology and aperture size were examined by field emission scanning electron microscopy. Finally, TCL with micro-structure was applied to solar cells for anti-reflection.
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Wen, Cheng-Ying, and 溫承穎. "Improvement of Anodic Aluminum Oxide Technique on GaN and Fabrication of Metal Particles for Surface Plasmon Study." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/12822886094137128369.
Full textAbstract:
碩士國立臺灣大學
光電工程學研究所
96
Anodic aluminum oxide (AAO) is a typical self-organized structure with nano-hole arrays. It has many application advantages, compared to e-beam lithography and focus ion-beam etching. In this thesis, we present the procedures for fabricatng AAO of different sizes and interpore distances using phosphoric acid and sulfuric acid as electrolytes. Then, the SiO¬2 nano-pore arrays of different interpore distances are fabricated using AAO as an etching mask. We discuss how to fabricate AAO on p-type GaN template. Then, we roughen the surface of a light-emitting diode (LED) using AAO as an etching mask. It is expected the light extraction of the LED can be enhanced. Next, the metal nano-particles are fabricated using AAO as an evaporation mask. The SP characteristics of Ag, Au, Cu nano-particles on undoped GaN templates are investigated from UV-visible transmission spectroscopy.
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Wen, Cheng-Ying. "Improvement of Anodic Aluminum Oxide Technique on GaN and Fabrication of Metal Particles for Surface Plasmon Study." 2008. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0001-2907200812081600.
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Chuang, Kai-Chieh, and 莊凱傑. "Investigation of Anodic Oxidation Technique for the Preparation of Ultra-thin Gate Dielectrics on Si and SiC Substrates." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/90879742009856676872.
Full textAbstract:
博士臺灣大學
電子工程學研究所
98
This dissertation was focused on the anodic oxidation (anodization) process. First, the anodization is used to improve the electricsl characteristics of high-k Al2O3 on Si substrate. Second, we grow SiO2 on n-type 4H-SiC substrate by anodization. An anodic field was added in aqueous nitric acid for the improvements of high-k Al2O3 on Si in both current density and reliability. After being annealed in furnace at 650℃ in N2, Al2O3 with equivalent oxide thickness (EOT) of 24-25Å are prepared. It was found that the leakage current, breakdown field, and stress induced leakage current were much improved without sacrificing the interfacial property. This improvement can be ascribed to the compensation oxidation process. On the other hand, MOS solar cells with different Al2O3 thickness are investigated. The best case can achieve an efficiency of 7.2% when the incident light intensity equals 5 mW/cm2. Also, room-temperature anodization is introduced to prepare ultra-thin SiO2 on n-type 4H–SiC. Both the interfacial layer and carbon cluster are not observed. The capacitance equivalent thickness (CET) is about 27-48 Å, and the breakdown field of the grown oxide is higher than 5 MV/cm. The hysteresis of capacitance-voltage curves can be negligible. The positive current conduction is mainly dominated by the Schottky emission, while negative-biased current is limited by carrier generation-recombination. Furthermore, the frequency parameters of anodization were investigated. It is shown that the SiO2 on n-type 4H–SiC substrate by scanning frequency anodization has higher oxide breakdown field and better interfacial properties than that by DC anodization. It is suggested that both the bulk and interface traps in the oxide can be compensated since the scanning frequencies are in close proximity to the response times of interface states. The energy conveyed from the scanning frequency can rebuild the defect bonds in the interfacial region.
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Yen, Ju-Hsin, and 鄢如心. "EFFECT OF COLD SEALING AND SEALING ADDITIVES ON THE SEALING OF THE ANODIC OXIDATION FILMS OF ALUMINUM BY PULSE CURRENT." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/25179147640974121702.
Full textAbstract:
碩士大同工學院
化學工程學系
84
In this study, the main purpose is to discuss the effects of sealing types by cold sealing and cold with additives on the properties of oxide film which is obtained in the anodizing process of aluminum A1100 by pulse current method. Three kinds of sealing type, such as cold sealing without additives, coldsealing with additives and hot water sealing are compared. The anodizing process is operated at constant voltage of 20V (various pulse current parameters are applied) in 10vol% sulfuric acid with bath temperature of 25℃. And the unsealed anodic oxide film with maximum microhardness of 275Hv can be obtained under the condition of 60% duty cycle, 500Hz frequency and 30min anodic durationtime. Cold sealing by nickel fluoride at room temperature is better than thatby other nickel salts. A sealed film (anodic duration time:20min) with weightgain of78.2 mg/dm2 and microhardness of 275Hv can be obtained under the sealingconditions of 20℃, pH=5, 5g/L nickel fluoride and 30min sealing time. The maximum value of gloss 27.8 can be obtained at sealing temperature of 10℃. When0.3g additives of aminopropyl triethoxysilane is added into the sealing solution of 5g/L nickel fluoride, the microhardness of 325Hv can be obtained. From the phosphoric-chromic acid dissolution test and acetic acud / sodium acetate dissolution test, result can be obtained that the better sealing quality is inthe order of cold sealing with additives>cold sealing without additives>hot water sealing.
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Chen, Ying-Ting, and 陳盈廷. "The Effect of Sodium Sulfate on Anodic Oxidation of 6061 Aluminum Alloy in Sulfuric Acid Baths by Using Experimental Design Method." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/34240394727763666011.
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碩士大同工學院
材料工程研究所
87
In this research, the method of experimental design was used as a process development tool for searching the significant factor which influences the hardness or thickness of Al6061 alloy anodic oxide films. There were two stages of experimental design method. First stage, five variables - temperature, duration time, current density, adding modifiers and the concentration of sulfuric acid was used. In this stage, the duration time factor is the most significant factor. Three variables including adding modifiers, duration time and the concentration of sulfuric acid was used in the second stage. The significant factor and the prediction model of this experiment was also studied. The best condition in these experiments of first stage is the condition with temperature at 5oC, duration time at 40 min and the concentration of sulfuric acid of 12 %. Hardness and thickness are 25 μm and 450 HV, respectively. The best condition in these experiments of second stage is the condition with adding modifiers of Na2SO4 2.3 g/l, temperature at 10oC and the concentration of sulfuric acid of 13%. Hardness and thickness are 12.6 μm and 322 HV, respectively.
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Su, Chung Jen, and 蘇忠仁. "EFFECTS OF MODIFIER-SODIUM SULFATE ON ANODIC OXIDATION OF ALUMINUM IN BORIC/SULFURIC ACID BATHS BY DIRECT CURRENT OR PULSE CURRENT." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/58982007088721959791.
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碩士大同工學院
化學工程學系
84
In this study, the main purpose is to find the optimal conditions for anodization in boric/sulfuric acid baths. In this experiment, the main electrolyte consists of 0~50g/l boric acid and 0~170g/l sulfuric acid, as well as 0~50g/l sodium sulfate are added as modifier. The anodizing process are operated by direct current or pulse current at cocstant voltage of 20v,at baths temperature of 25 ℃ and at constant pulse frequency of 500Hz. The results show the changing duty cycle of pulse current, and adding the sodium sulfate are able to obtain the anodic oxide film with better properties. And the properties of the anodic oxide film obtained in mixed acid baths are better than those in sulfuric acid bath. The optimal conditions for the experiment are as follows:(1) adding 50 g/l sodium sulfate into 30g/l boric acid and 170g/l sulfuric acid baths at frequency of 500Hz, duty cycle of 60% and duration time of 50 minutes that can obtain the film thickness of 70um.(2) adding 30g/l sodium surfate into 10g/l boric acid and 170g/l sulfuric acid bathsat frequency of 500Hz, duty cycle of 80% and duration time 30 minutes that can obtain the film microhardness of 576Hv. (3) The distribution of L- , a- and b-valueare no regulations in mixed acid baths. (4) In 50g/l boric acid and 70g/l sulfuricacid baths at frequency of 500 Hz, duty cycle of 20% and duration time of 10minutesthat can obtain a gloss of 88.2.
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Chang, Fan, and 張帆. "Surface modification of pure Aluminum and hot-dip aluminized carbon steel by micro-arc oxidation technique." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/23165238815979282588.
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碩士國立臺灣科技大學
機械工程系
102
Recently, the micro-arc oxidation (MAO) or the so-called plasma electrolytic oxidation (PEO) process has been widely studied and applied in industries due to its ability to create functional oxide layers on light metals. In this work, a high power current pulse power supply was used for the micro-arc oxidation coating on surfaces of pure aluminum and the hot-dipped aluminized steel substrates. The first stage of the experiment was controlling the duty cycle and frequency of power supply to fabricate five different MAO coatings on the pure Al. The second stage was a hybrid method consisting of the hot-dipped aluminizing (HDA) and MAO processes to deposit a composite ceramic coating on the surface of carbon steel plate. The HDA of carbon steel plate was executed at 710oC for 1 min. The duty cycle and frequency of MAO processes were adjusted to fabricate three different HDA plus MAO coatings. The phase analysis and microstructure of coatings were determined by X-ray diffractometer (XRD) and scanning electron microscopy (SEM), respectively. The hardness and adhesion of coatings were determined by the nanoindenter and scratch tester. The corrosion resistance of coatings was evaluated by the potentiodynamic polarization test in 0.5M H2SO4 aqueous solution. It was found that the peak power density increased with decreasing duty cycle at fixed frequency. Meanwhile, the thickness and roughness of MAO coating also increased. On the other hand, the peak power density and thickness of MAO coating increased with increasing frequency at fixed duty cycle. The main elements of the plasma were Al and Na species during the MAO process on the HDA steel surface. The intensity of Na plasma increased with reaction time. For the MAO coating on the HDA steel surface, the surface roughness slightly increased and the hardness greatly enhanced to higher than 15 GPa. In addition, the corrosion resistance of the MAO coating also improved effectively.
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Wang, Dinn-Jie, and 汪殿杰. "The Hybrid Anodic Treatment Technique applies research in the Metal Ornament Design─Aluminum and Titanium metallic material as an example." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/88071626858330520335.
Full textAbstract:
碩士實踐大學
產品與建築設計研究所碩士在職專班
96
The Hybrid Anodic Treatment technology, is refers to the anodic treatment technology to unify other surface treatment technology the application way, this research aim is discussing this kind of technology to apply in the Aluminum and the Titanium Metal Ornament design . The research process by the chemical treatment formula optimization experiment, by Taguchi Method, establishes the anodic treatment standard operational procedure which the research institute needs; The combination stamping, the sand blasting, the corrosion, the dyeing (against dye) and surface treatment technologies and so on resin, the development hybrid anodization treatment technology, provides the Metal Ornament design reference. The creation research part, uses the Semantic Differential Method, after anodic treatment, the material texture image's remarkable attribute analysis is as follows: light, opening, young with decoration, takes tests using the anodic treatment technology design; The accessories case's shape design, by Seeing Imagery (Spiral), the Imagining Imagery (Hollows), the Drawing Imagery (Repetition) three type imagery, because of the image analysis, transformed, the strengthened project approach, the shape union which agrees with the material image, the manufacture related ornament case. The research conclusion because of the actual product case's confirmation, this Hybrid Anodic Treatment , may have the unique material texture image, its diverse change's color effects, have the surface layer three-dimensional characteristic, has both practical and the decoration function.
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Morgenstern, Roy. "Anodische Oxidation von kupferhaltigen Aluminiumlegierungen." 2019. https://monarch.qucosa.de/id/qucosa%3A35699.
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Hochfeste kupferhaltige Aluminiumlegierungen gelten gemeinhin als „schwer“ anodisierbar, deshalb werden in der vorliegenden Arbeit werkstoffseitige und prozessseitige Maßnahmen zur Verbesserung der Schichtqualität erforscht. Zur eindeutigen Abgrenzung des Einflusses der Cu-Verteilung vom Einfluss anderer Legierungselemente und Verunreinigungen wurde für die Anodisierexperimente zusätzlich zur kommerziellen Legierung EN AW-2024 die hochreine Modelllegierung AlCu4 als Untersuchungswerkstoff gewählt. Insbesondere für die Modelllegierung AlCu4 konnte erstmals eine systematische Veränderung des Schichtbildungsmechanismus beschrieben werden. Mit zunehmender Ausscheidungsbildung nimmt das Ausmaß der Sauerstoffentwicklung ab, woraus erhöhte Schichtdicken und -härten folgen. Die nach Anodisieren der warmausgelagerten Zustände erhaltenen Schichtmikrostrukturen wurden erstmals im Rahmen dieser Arbeit mittels Rasterelektronenmikroskopie beschrieben. Aufgrund reduzierter Schichtrücklösung sind auch auf der Legierung EN AW-2024 im warmaus-gelagerten und überalterten Zustand höhere Schichtdicken und -härten für eine Elektrolyttemperatur von 20 °C erzielbar. Bei einer Elektrolyttemperatur von 5 °C können die Schichtdicke und -härte vor allem durch Zugabe von Additiven zum schwefelsauren Grundelektrolyt gesteigert werden. Im Unterschied zu konventionellen organischen Additiven resultiert die Zugabe von Salpetersäure darüber hinaus in einer Absenkung der Anodisierspannung zu Prozessbeginn und damit in einer Reduzierung der erforderlichen elektrischen Energie. Mit steigender Additivkonzentration nimmt jedoch die Ritzbeständigkeit der Schichten infolge erhöhter Mikrorissigkeit ab. Es ist folglich ein Optimum aus Schichthärte und Mikrorissigkeit zu finden.High-strength aluminum-copper alloys are generally recognized to be “hardly” anodizable. Hence, the influences of material and process parameters were investigated within this work in order to improve the coating properties. Apart from the commercial alloy EN AW-2024, the high purity model alloy AlCu4 was used for the anodizing experiments in order to distinguish between the influence of the copper distribution and the influence of other alloying elements and impurities. Regarding the model alloy AlCu4, a systematic change of the coating growth mechanism was described for the first time. The extent of oxygen evolution decreases with the intensification of the precipitation leading to increased coating thickness and hardness. In this work, the coating microstructures, resulting from the anodic oxidation of the artificially aged conditions, were described by scanning electron microscopy, for the first time. Due to reduced chemical dissolution of the coatings, higher coating thickness and hardness can also be achieved after room-temperature anodizing of the alloy EN AW-2024 in the artificially aged conditions. For hard-anodizing at an electrolyte temperature of 5 °C, the coating thickness and hardness can be particularly improved by using additives in combination with the sulfuric acid base electrolyte. Beyond that and in contrast to the effect of conventional organic additives, the addition of nitric acid enables the reduction of the anodizing voltage at the beginning of the process and therefore, the reduction of the required electrical energy. However, the scratch resistance of the coatings decreases with increasing additive concentration due to the occurrence of micro crack networks. Consequently, the coating hardness and the amount of microcracks have to be optimized in order to meet concrete application requirements.
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Li, Li-Guo, and 李立國. "Strain Release of InGaN/GaN Quantum Wells through Nano-hole Fabrication and Formation of Metal Particles for Surface Plasmon Study with the Anodic Aluminum Oxide Technique." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/64807688490105296426.
Full textAbstract:
碩士國立臺灣大學
光電工程學研究所
96
In this research, we fabricate anodic alumina oxide (AAO) on GaN and InGaN/GaN quantum well (QW) structure. With the AAO technique, we can fabricate a thin aluminum oxide film with nano-pore array on the nitride structure, which is used as a mask to deposit metal nano-particle arrays on to study the surface plasmon (SP) characteristics, or to release the strain in the QW. Our first study is about the SP characteristics of a silver or gold nano-particle array on GaN template. We change the AAO process condition to control the hole diameter and interpore distance such that we can vary the particle size and density of the metal nano-particle array. We observe the SP absorption spectra and its resonance frequencies of different particle sizes and densities. The second study is about the strain relaxation phenomenon by fabricating nano-hole array patterns with the AAO technique on an InGaN/GaN QW structure. The effective strain relaxation, leading to the significant enhancement of emission efficiency and reduction of quantum-confined Stark effect (QCSE), in a high-indium InGaN/GaN QW structure via nano-pore fabrication on the sample surface with the anodic aluminum oxide technique is demonstrated. By generating nano-pores of 60 nm in size, 4.71 x 109 cm-2 in pore density, and a depth several nm above the QW, the internal quantum efficiency (IQE) can be increased by about three times and the QCSE is reduced by 2.5 times while the emission spectrum is blue-shifted by 14 nm in the green range. With this approach, it is possible to achieve a higher IQE and a smaller QCSE by relaxing the built-in strain of a higher-indium QW structure and blue-shifting its emission, when compared with a lower-indium sample of the same emission spectrum as the blue-shifted one.
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Li, Li-Guo. "Strain Release of InGaN/GaN Quantum Wells through Nano-hole Fabrication and Formation of Metal Particles for Surface Plasmon Study with the Anodic Aluminum Oxide Technique." 2008. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0001-2607200817144200.
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