Papers by Keyword: Anodization

Abstract: Recently, demand for this Anodic Alumina Oxide (AAO) has been raised throughout the year due to its unique and special properties that will bring many benefits to the nanotechnology industry. AAO is the self-organized porous alumina produced by anodizing aluminum and can also be seen as nanotube arrays with honeycomb-like structures. Throughout these centuries, many research has been done in order to study the optimum parameter to produce high-quality AAO. This paper is specifically to investigate the effect of anodization voltage on the structural formation of AAO by using anodization of the aluminum process. A porous alumina template was prepared by using a difference voltage range of 20 V – 30 V in 0.3 M of oxalic acid; a copper wire was used as the cathode electrode and an aluminum template was used as an anode. It is observed that after the anodization process, there is a significant increase in current density at every voltage increment, as well as an increase in the size of the nanopores in AAO. The morphology and phase composition were characterized by using Field Emission Scanning Electron Microscope (FESEM), Energy Dispersive X-ray Spectroscopy (EDX) and Fourier Transform Infrared Spectroscopy (FTIR).

Abstract: This article focused on investigating the influence of current density on the morphology and structure of silver nanoparticles (n-Ag) electrodeposited on anodized titanium substrates (denoted as TiO₂/Ti) on the surface. The TiO₂/Ti substrate served as the cathodic electrode placed in an electrolyte solution containing ionic [Ag(NH₃)₂]⁺ complex solution. The n-Ag/TiO₂/Ti samples were synthesized at current densities ranging from 0.2 A/dm² to 0.5 A/dm² for 20 seconds at room temperature. The study performed morphological and surface composition analysis of n-Ag/TiO₂/Ti using Field Emission Scanning Electron Microscopy (FESEM) and X-ray Diffraction (XRD) techniques. Additionally, the study assessed the electrochemical properties using the AutoLab system with Nova 2.1 software, based on Tafel curve measurements to compare the corrosion resistance of the samples before and after modification.

Abstract: The article shows the process of preparing an oxide layer on the surface of titanium for use in industrial catalysis. Data from physical and chemical studies are presented, namely microhardness, porosity, thickness, specific surface area, adhesion and thermal stability of the active layer.To determine the physicochemical characteristics of the resulting oxide layer, the following analysis methods were used: X-ray diffraction analysis (XRD), X-ray diffraction phase analysis (XPA), X-ray absorption analysis (XRA), and X-ray fluorescence analysis. The thickness of the oxide layer depending on the duration of anodization was estimated by optical microscopy.

Abstract: Porous Anodic Aluminum oxide (PAAO) is a porous oxide layer resulting from anodization. The structure of PAAO is influenced by anodization parameters, i.e., voltage and electrolyte composition. Increasing anodization voltage can affect the process of pore formation and oxide growth during anodization. Adding additives such as ethanol, propanol, and polyethylene glycol (PEG) can increase pore regularity and affect the structure of PAAO. In this study, tobacco extract (TE) was added to the oxalic acid-based anodizing solution. TE has many active compounds that may affect pore formation and oxide growth. Morphological analysis shows decreased pore diameter when adding tobacco extracts with concentrations of 0, 0.1, and 0.5 g/L, namely 43.92, 41.42, and 37.8 nm at anodization voltage 40 V. In anodization with a voltage of 60 V, a decrease in pore diameter was obtained with 46.47, 34.24, and 26.8 nm for adding tobacco extract 0, 0.1, and 0.5 g/L. The thickness of PAAO increases from 6.45 µm to 16.87 µm with increasing anodization voltage and tobacco extract concentration. The increase of tobacco extract concentration can lead to the decrease of the XRD peak intensity, where the sequence of the most significant decrease was observed for the peaks of (111), (220), (200), and (311), respectively. A decrease in the intensity ratio of (111) and (220) AAO peaks indicates the influence of tobacco extract on the anodization process. Further thermal analysis by Thermo-gravimetric (TG) shows an increase in mass loss from 1.47 to 5.37% with increasing tobacco extract concentration from 0 g/L to 0.5 g/L. TG results indicate the incorporation of tobacco extract in the inner pore wall.

Abstract: A white light, i.e., Fabry-Perot, interferometry was unprecedently applied to determine the rate change of the current density (J) of aluminum samples during the anodization processes of the samples in aqueous solutions. The current density(J) values were obtained by Fabry-Perot interferometry rather than the direct current (DC) or alternating current (AC), methods. Therefore, the abrupt rate change of the J was called electrochemical-emission spectroscopy. The anodization of the aluminum samples was conducted by an external DC source in 0.0,2,4,6,8,10% sulfuric acid (H₂SO₄) solutions at room temperature. In the meantime, the Fabry-Perot interferometry was used to determine the difference between the J of two subsequent values, dJ, as a function of the elapsed time of the DC experiment for the aluminum samples in 0.0,2,4,6,8,10% H₂SO₄ solutions. The Fabry-Perot interferometry was based on a fiber-optic sensor in order to make real time-white light interferometry possible at the aluminum surfaces in the sulfuric acid solutions. As a result, a new spectrometer was developed based on the combination of the Fabry-Perot, i.e., white light, interferometry and DC method for studying in situ the electrochemical behavior of metals in aqueous solutions.

Abstract: Electrochemical anodization is a unique surface modification technique for modifying the titanium surface. Electrochemical alteration of titanium surface increases the material efficiency in biomedical applications. The present research work analyses the fabrication of TiO₂ nanotubes by increasing the water content and the various results and characterization enhance the cell viability. The influence of water content in electrolytes improves cell viability and at the same time, it is non-toxic. The surface morphologies were studied with HR-SEM, phase transformation was characterized using X-ray diffraction and cell viability was investigated with MTT assay by NIH-3T3 fibroblast cells incubation time for 48 hours (standard time incubation).

Abstract: Anodizing is an electrochemical process to produced anodic coatings for improving magnesium (Mg) properties such as corrosion-resistant. In this study, anodizing of pure magnesium in 1 M NaOH electrolyte for 1800 s and at 21 °C and different constant current or voltage was investigated. The effect of voltage and current on morphology and thickness of the resulting anodic layers was evaluated by scanning electron microscopy (SEM) equipped with EDX analyser. The thickness of the produced layers was determined to utilize digital image analysis. The results showed that using lower current of 0.08 A non-compact anodic layer was produced. When a higher current of 0.2 and 0.5 A was used compact and thicker anodic layers were produced compare to lower current of 0.08 A. The anodic layer produced at a constant voltage of 20 V was rougher, thicker and contained microcracks compare to anodic layers formed at constant voltage of 12 V and at constant current (0.2 and 0.5 A).

Abstract: Ti-6Al-4V as an implant material has bio-inert properties, so it does not support any tissues or bone cells reaction. This study aims to increase the tendency of osteoblast's cell attachment to the surface of implant Ti-6Al-4V by fabricating nanotube structure on the surface by anodization. This study also conducted to study the effect of elements from titanium alloys and organic electrolytes on the mechanism of formation of nanotube structures. The anodization method was chosen because it was easy to do, effective, and inexpensive. The samples were prepared by ground and polished, then washed by ultrasonic. Anodization used organic electrolytes in the form of a mixture of ethylene glycol, 0.5 M NH₄F, and 4 w.t% deionized water. The study of the effect of voltage and duration time was carried out to understand the mechanism of nanotube formation, through morphological observation on the surface and cross-section area of nanotubes using SEM and characterization of elements using EDS, diameter, and length of highly ordered nanotubes was observed. The results of the characterization showed that the tube diameter is adjusted by the voltage, while duration time influence the tube length, with a linear relationship, so the widest diameter achieved at 40V 5h, but the longest tube achieved at 30 V 5h. Whereas for 5h duration, the upper part of the tube collapsed and disintegrated. The fluoride ions incorporated at the tube surfaces formed fluoride-titanium oxide cubic agglomerates, and the whole nanotube surface was oxide.

Abstract: Titanium dioxide is a widely-investigated semiconductor photocatalyst due to its wide availability and low cost. Although it has been successfully used in the photocatalytic treatment of various organics in wastewater, it remains a challenge to modify its structure to achieve enhanced catalytic properties at a wider light spectrum. Doping with transition metals was seen to narrow its optical band gap yet synthesis routes have been largely limited to the use of high-end equipment. Herein we demonstrate the use of a simpler one-pot approach to synthesize nanoporous arrays of silver-doped titanium dioxide nanotubes (Ag-TiNTs) by double anodization of titanium sheets. The synthesized Ag-TiNTs have an average inner diameter of 58.68 nm and a wall thickness of 16.46 nm. ATR-FTIR spectroscopy revealed its characteristic peaks attributed to O-Ti-O bonds. Silver doping increased the lattice volume and crystallite size of anatase with a corresponding decrease in the degree of crystallinity due to the introduction of impurity Ag atoms in its tetragonal structure. Silver was homogeneously distributed across the nanotube surface at an average loading of 1.41 at. %. The synthesized Ag-TiNTs were shown to have a superior photoelectrocatalytic activity in degrading C.I. Basic Blue 9 under UV illumination with a pseudo-first-order kinetic rate of 1.0253 x 10^-2 min^-1. Most importantly, the Ag-TiNTs are photoelectrocatalytically-active even at a low Ag loading.

Abstract: Electrochemical techniques can be used in the various fields, such as anodization, deposition, etching, polishing, pitting, and corrosion applications. In this paper, we focus on the high quality coloring anodic film fabrication. In the prior technologies, anodization generally has the main purpose of surface decoration or corrosion resistance. However, in the high technologies, the characteristics of film thickness, anti-voltage value, surface roughness, surface color and hardness of the anodic film have been strict requirements. The key parameters of anodization such as, electrolyte composition, current-voltage curve pattern, temperature, current density, time, final voltage, efficiency, and electricity affect the quality of anodic film. In order to make a high quality anodic film, this paper provided a detail anodization process and discussed the quality of anodic film.