Papers by Keyword: Anodic Oxidation

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Authors: I. Montero, J.M. Albella, L. Vázquez
251
Authors: Syazwan Hanani Meriam Suhaimy, Chin Wei Lai, Sharifah Bee Abd Hamid, Mohd Rafie Johan, M.R. Hasan
Abstract: Self-organized titanium dioxide (TiO2) nanotubes (NTs) arrays were successfully fabricated via electrochemical anodization of titanium (Ti) foil in an organic electrolyte containing 5wt% of fluoride content. The present work compares two different organic electrolytes (glycerol and ethylene glycol) for the growth of self-organized TiO2 nanotubes by using anodic oxidation strategy. The resultant TiO2 NTs were then subjected to thermal annealing for manipulating the crystalline structure. The SEM images indicated changes in surface morphology of the TiO2 NTs in different electrolytes. It was found that the NT’s dimensional was 56.00nm based on the SEM analyses. Both samples exhibited good photocurrent response; however, TiO2 NTs synthesized in ethylene glycol electrolyte showed promising photocurrent response of 0.385 mA.
429
Authors: Jia Ju An
Abstract: A process in anodic oxidation with high current density and wide temperature range was researched for high speed forming film on the top surface of aluminum piston. The oxidation parameters is a concentration of 18% H2SO4 solution-based liquid, current density of 5.5~8A/dm2, temperature range-5~20°С , the oxidation time for the 0~60min. Pulse power and cooling equipment co-work to produce the film thickness up to 107μm, film speed was about 1.78μm / min. SEM indicates that the porous layer was made of the regular array columnar “cells” which parallel arrange and grow perpendicular to substrate.
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Authors: Ning Zhang, Wei Qing Han, Lian Jun Wang
Abstract: The oxidation of sulfide was investigated at a potential of about -0.1 V, 60 °C and electrolyzation time of 48 h, the sulfide ions were oxidized to sulfur and polysulfide, and the predominant polysulphide was S22-. The behavior of the anodic oxidation was highly dependant on the applied temperature and the concentration of the sulfide ions.
1367
Authors: Roy Morgenstern, Daniela Nickel, Dagmar Dietrich, Ingolf Scharf, Thomas Lampke
Abstract: Aluminium matrix composites (AMCs) consisting of high-strength, age-hardenable aluminium alloys and homogeneously dispersed hard particles open up new possibilities in designing light-weight material based security related structures. The susceptibility of the matrix alloy to selective corrosion can be reduced significantly by anodic oxidation. A powder-metallurgical processed alloy AlCu4MgMn with hard particles and a commercial wrought alloy for reference were used for the investigations.In order to control the microstructure of anodic aluminium oxide (AAO) formed on AMCs, it is necessary to understand the formation mechanism and the influencing parameters. Therefore in a first run, the anodizing behaviour of matrix alloy was separated from the behaviour of hard particles. The AAO coatings show small growth rates on the matrix and the reference alloy accompanied by a complex pore structure which differs from the ordered vertical pore structure on pure aluminium. Depending on the type and the size as well as the anodizing parameters, the particles are either incorporated into the AAO coating unchanged or partly resp. completely oxidized. The AAO microstructure changes significantly in dependence of the anodizing parameters. It is shown that a technically relevant coating thickness can be achieved on AMCs by choosing appropriate process parameters.
636
Authors: Judith Moosburger-Will, Matthias Bauer, Fabian Schubert, Omar Cheick Jumaa, Siegfried R. Horn
Abstract: We investigate the effects of static and dynamic anodic oxidation treatment on the surface chemical composition and functionality of carbon fibers. During static treatment, the electrolytic surface oxidation process is performed on a spatially fixed carbon fiber bundle, while in the dynamic process a moving, continuous carbon fiber tow is oxidized. In both treatment modes electrolytic current density and treatment time were varied. Surface chemical composition and functionality of the resulting carbon fibers were analyzed by x-ray photoelectron spectroscopy. A good agreement between the chemical composition and the functionality of fibers from static and dynamic anodic oxidation treatment is found. This suggests that results from static fiber treatment in a variable, easy to handle laboratory setup can be applied to dynamic anodic oxidation process conditions on a large scale.
440
Authors: Mohamad Ali Selimin, Noor Haafiza Mohd Idru, Hasan Zuhudi Abdullah
Abstract: Anodic oxidation (AO) is a chemical method which used to produce a bioactive layer (oxide) of titanium (Ti). The aim of this study is to evaluate the effect of anodic oxidation upon Ti foil in acetic acid (C2H4O2). The anodic oxidation was performed by varying the applied voltage (10 – 200 V) and concentration of the electrolyte (0.5, 1.5 and 3.0 M of C2H4O2). After anodic oxidation, the Ti specimens were soaked in simulated body fluid (SBF) to observe the precipitation of hydroxyapatite (HAP). The Ti sample was characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM) after anodic oxidation and SBF. The precipitation of apatite after soaked in SBF was observed using SEM. From this study, the applied voltage range from 100 to 200 V at low and high concentration of acetic acid resulting in the porous surface of anatase. The arcing process occurred during the oxidation process which lead to the formation of anatase and sites for HAP growth (nucleation site). The SBF result shows that the anodised Ti is suitable to be applied in biomedical especially as implant.
81
Authors: Mohamad Ali Selimin, Maizlinda Izwana Idris, Hasan Zuhudi Abdullah
Abstract: Anodic oxidation (AO) is an electrochemical method which used to change the bio-inert (smooth) to bio-active (rough) layer of titanium (Ti) surface. The aim of this study is to evaluate the effect of anodic oxidation on characteristics of Ti in acetic acid (C2H4O2) under various conditions. Anodised Ti were prepared using anodic oxidation method on the surface of Ti films in acetic acid by varying the applied voltage (50 – 350 V) and current density (25, 50 and 75 mA.cm-2) for 10 min at room temperature. The anodised Ti films were characterised using digital camera, field emission scanning electron microscopy (FESEM), and atomic force microscopy (AFM). The results show that, roughness of the Ti films was increased with increment of applied voltage and current density. The anodised effects during anodic oxidation process change the surface roughness (porosity) of the Ti surface which meets the biomaterial need as implant material. This characteristic is needed to promote the formation of apatite when soak in simulated body fluid (SBF).
455
Authors: Hasan Zuhudi Abdullah, Pramod Koshy, Charles Christopher Sorrell
Abstract: Anodic oxidation is an electrochemical method for the production of a ceramic film on a metallic substrate. It involves the use of an electrical bias at relatively low currents while the substrate is immersed in a weak organic acid bath. The films produced are usually dense and stable, with variable microstructural features. In the present work, ceramic films of the anatase and rutile polymorphs of TiO2 were formed on high-purity Ti foil (50 μm) using mixtures of β-glycerophosphate disodium salt pentahydrate (β-GP) and calcium acetate monohydrate (CA) solutions. The experiments were carried out at varying voltages (150-350 V), times (1-10 min), and current density (10 mA.cm-2) at room temperature. The ceramic films were characterised using digital photography, glancing angle X-ray diffraction (GAXRD), and field emission scanning electron microscopy (FESEM). The thicknesses of the films on Ti were measured using focused ion beam (FIB) milling. The colour, microstructures, and thicknesses of the films were seen to be strongly dependent on the applied voltage. At bias <200 V, single-phase anatase was observed to form on Ti, while at higher bias (250 V), rutile formed due to the arcing process.
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