Nanoporous Anodic Aluminum Oxide (AAO) Thin Film Fabrication with Low-Grade Aluminium

2016 ◽  
Vol 872 ◽  
pp. 152-156
Author(s):  
Peerawith Sumtong ◽  
Apiluck Eiad-Ua ◽  
Khattiya Chalapat
Keyword(s):  
Aluminum Oxide ◽  
Anodic Aluminum Oxide ◽  
Pore Diameter ◽  
Average Pore Diameter ◽  
Process Conditions ◽  
Low Grade ◽  
Average Pore ◽  
Aluminium Substrate ◽  
Anodization Time ◽  
Anodic Aluminum

Anodic aluminum oxide (AAO) is well known for its nanoscopic structures and its applications in microfluidics, sensors and nanoelectronics. The pore density, the pore diameter, and the interpore distance of an AAO substrate can be controlled by varying anodization process conditions. In this research, the self-organized two-step anodization is carried out with a low-grade (Al6061) aluminium substrate using a 40V voltage at the temperature of 2 to 5 °C. Three experiments are done with the anodization time of 24 hours, 48 hours and 72 hours. The structural features of AAO are characterized by a field emission electron microscope (FE-SEM). The data from FE-SEM show that the average pore diameter increases with the anodization time, and that the Al6061 aluminium substrate can be used to fabricate a nanoporous AAO film with an average pore diameter smaller than 17 nanometers.

Fabrication of Low Cost Membrane from Anodic Aluminum Oxide

2017 ◽  
Vol 751 ◽  
pp. 363-367
Author(s):  
Peerawith Sumtong ◽  
Apiluck Eiad-Ua
Keyword(s):  
Aluminum Oxide ◽  
Anodic Aluminum Oxide ◽  
Pore Diameter ◽  
Average Pore Diameter ◽  
Process Conditions ◽  
Low Grade ◽  
Pore Density ◽  
Average Pore ◽  
Anodic Aluminum ◽  
Interpore Distance

Anodic Aluminum Oxide (AAO) membrane has been successfully fabricated from two-step anodization with aluminum low grade (Al6061). The pore density, the pore diameter, and the interpore distance can be controlled by varying anodization process conditions. However, there are limits to control the mechanical strength and growth of AAO arrays, such as pore density, pore diameter and interpore distance. In this research the self-organized two-step anodization is carried out varying time at 24, 48 and 72 hours, respectively with 40V at the low temperature 2-5°C. The optimum conditions of AAO with two-step anodization is 40V for 48 hr. Finally, AAO substrate is separated from aluminum low-grade and enlarged pore diameter with pore widening process by 5% H3PO4. The physical properties were investigated by mean of field emission scanning electron microscope (FE-SEM) show that the average pore diameter and average interpore distance increase with the anodization time. Al6061 Aluminum substrate can be used to fabricate a nanoporous AAO film with an average pore diameter and average interpore distance larger than 70 and 90 nanometers, respectively but less mechanical stability.

scholarly journals Influence of the anodization conditions and chemical treatment on the formation of alumina membranes with defined pore diameters

2021 ◽  
Author(s):  
Iwona Dobosz
Keyword(s):  
Aluminum Oxide ◽  
Chemical Treatment ◽  
Anodic Aluminum Oxide ◽  
Pore Diameter ◽  
Operating Conditions ◽  
Oxide Growth ◽  
Pore Density ◽  
Anodic Aluminum ◽  
Pore Widening ◽  
Oxide Membranes

AbstractPorous anodic aluminum oxide membranes were fabricated via two-step anodization of aluminum in 0.3 M H2C2O4, 0.3 M H2SO4 and 0.17 M H3PO4 solutions. The parameters of the oxide film such as: pore diameter (Dp), interpore distance (Dc), porosity (P) and pore density (ρ) can be completely controlled by the operating conditions of the anodization. Additionally, the pore diameters and pore density can be controlled via a chemical treatment (pore opening/widening process). The effect of anodizing conditions such as the applied voltage, type of electrolyte and purity of the substrate on the rate of porous oxide growth are discussed. The obtained results were compared with the theoretical predictions and data that has been reported in the literature. The influence of the duration of chemical etching on the structural features of the oxide membranes was studied. On the based on qualitative and quantitative FFT analyzes and circularity maps, it was found that the nanostructures of anodized aluminum have the maximum order under certain specified conditions. The presence of alloying elements affects not only the rate of oxide growth but also the morphology of the anodic aluminum oxide. The rate of oxide growth depends on the electrolyte type and temperature. During chemical treatment of the oxide films pore diameter increases with the pore widening time and the highest pore widening was observed in phosphoric acid solution.

Templated fabrication of nanostructured Ni brush for hydrogen evolution reaction

2010 ◽  
Vol 25 (10) ◽  
pp. 2001-2007 ◽  
Author(s):  
Sheng-Chieh Lin ◽  
Yu-Fan Chiu ◽  
Pu-Wei Wu ◽  
Yi-Fan Hsieh ◽  
Cheng-Yeou Wu
Keyword(s):  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Anodic Aluminum Oxide ◽  
Electroless Deposition ◽  
Pore Diameter ◽  
Pore Channel ◽  
Average Pore ◽  
Anodic Aluminum ◽  
Anodization Process ◽  
Pore Opening

We fabricated a nanostructured brush by carrying out Ni deposition on a through-channel anodic aluminum oxide (AAO) template, followed by removal of the AAO skeleton. The AAO was prepared by a two-step anodization process resulting in pore diameter and thickness of 350 nm and 40 μm, respectively. Subsequently, the AAO underwent an electroless deposition involving sensitization, activation, and Ni plating, in conjunction with polyethylene glycol used as the inhibitor to prevent premature closing of pore opening. After deliberate control in relevant parameters, we obtained a conformal Ni overcoat along every pore channel leading to a reduced average pore diameter of 78 nm. Afterward, the sample was immersed in a KOH solution to remove the AAO structure, forming freestanding Ni tubules in a brush configuration. The nanostructured brush revealed considerable enhancement for hydrogen evolution reaction in both current-potential polarization and galvanostatic measurements, which were attributed to the increment in apparent surface area.

Fabrication of Low Cost Anodic Aluminum Oxide (AAO) Tubular Membrane and their Application for Hemodialysis

2012 ◽  
Vol 550-553 ◽  
pp. 2040-2045 ◽  
Author(s):  
Ajab Khan Kasi ◽  
Jafar Khan Kasi ◽  
Mahadi Hasan ◽  
Nitin Afzulpurkar ◽  
Sirapat Pratontep ◽  
...  
Keyword(s):  
Anodic Aluminum Oxide ◽  
Pore Diameter ◽  
Low Cost ◽  
Membrane Thickness ◽  
Low Grade ◽  
Fluid Filtration ◽  
Tubular Membrane ◽  
Anodic Aluminum ◽  
Self Organized ◽  
Impurity Defects

This paper reports the fabrication of AAO tubular membrane using 99.35% and 99.56% pure Al and their potential application for hemodialysis. Here we discussed the effect of impurity on membrane structure. We found that the self organized structure of AAO nanochannels minimizes impurity defects in membrane. If micro size impurity blocks the generation of nanochannels then the neighboring nanochannels bend and make branches to fulfill that gap. We observed that if impurity size is less than the AAO membrane thickness then it does not produce any micro size hole. In low grade Al the periodic hexagonal order was disturbed however there was no big difference in pore diameter. It was observed that such type of membrane do not have any leakage and it can be used for fluid filtration. The fabricated tubular membrane was used for hemodialysis successfully. The hemodialysis results show that AAO tubular membrane can be used for both diffusive and convective filtration

Fabricating Anodic Aluminum Oxide by Anodic-Oxidation

2011 ◽  
Vol 383-390 ◽  
pp. 5522-5525
Author(s):  
Ji Yan He ◽  
Jian Dan Ren ◽  
Yan Bin He
Keyword(s):  
Aluminum Oxide ◽  
Anodic Oxidation ◽  
Anodic Aluminum Oxide ◽  
Pore Diameter ◽  
Pore Distribution ◽  
Aao Template ◽  
One Dimensional ◽  
Anodic Aluminum

Uniform parallel pores and controllable pore diameter make Anodic Aluminum Oxide (AAO) membrane one of the best materials in synthesis of one-dimensional nano-structured material. High orderly AAO template was prepared by anodic-oxidation. The prepared AAO membrane’s apertures ranged from 30 nm to 75 nm. Within a few microns, holes were orderly arranged. The fabricating methods of AAO template in different electrolyte were studied and the factors which affect the pore distribution, such as electrolyte types, voltage and concentration were discussed.

Role of Oxalate Anions on the Evolution of Widened Pore Diameter and Characteristics of Room-Temperature Anodic Aluminum Oxide

2017 ◽  
Vol 164 (4) ◽  
pp. C121-C127 ◽  
Author(s):  
C. K. Chung ◽  
D. Dhandapani ◽  
C. J. Syu ◽  
M. W. Liao ◽  
B. Y. Chu ◽  
...  
Keyword(s):  
Aluminum Oxide ◽  
Anodic Aluminum Oxide ◽  
Room Temperature ◽  
Pore Diameter ◽  
Anodic Aluminum

Fabrication of Self-Organized Porous Anodic Alumina Film in Malonic Acid

2014 ◽  
Vol 941-944 ◽  
pp. 1271-1274
Author(s):  
Di Ma ◽  
Shu Bai Li ◽  
Long Gui Xu ◽  
Xin Yan Dong ◽  
Xiu Ying Hu
Keyword(s):  
Aluminum Oxide ◽  
Malonic Acid ◽  
Anodic Aluminum Oxide ◽  
Pore Diameter ◽  
Porous Anodic Aluminum Oxide ◽  
Anodic Aluminum ◽  
Self Organized ◽  
Ordered Array ◽  
The One ◽  
Imagej Software

The surface of porous anodic aluminum oxide (AAO) film anodizing in malonic acid, which is characterized by Scanning Electron Microscope (SEM) and ImageJ software. There are disorderly tiny pores or stripes on the first once anodizing surface. Pore diameter, pore density and porosity are decided by the first anodizing process. With anodizing step increased, pore diameter of the membrane decreased. Two-step anodization improves the order of PAA membrane greatly, which is processed on the basic of the ordered array pits at the aluminum that is observed after removing membrane of the one-step anodization. According to the experiments, porous anodic aluminum oxide (PAA) was prepared in 1.0 mol/L malonic acid, its pore diameter increased and porosity decreased with anodizing voltage increased.

Fabrication of Thinner Anodic Aluminum Oxide Based Microchannels

2012 ◽  
Vol 550-553 ◽  
pp. 2046-2050 ◽  
Author(s):  
Mahadi Hasan ◽  
Ajab Khan Kasi ◽  
Jafar Khan Kasi ◽  
Nitin Afzulpurkar ◽  
Supanit Porntheeraphat ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Aluminum Oxide ◽  
Anodic Aluminum Oxide ◽  
Ph Value ◽  
Membrane Thickness ◽  
Average Pore ◽  
Wall Width ◽  
Fluid Filtration ◽  
Anodic Aluminum ◽  
Filtration System

When thickness of a membrane reduces its mechanical properties go down but thinner the membrane better the performance of the membrane in terms of filtration. In this research we fabricated a fluid filtration system with a very thin anodic aluminum oxide (AAO) membrane. The system consists of microchannels at one side of membrane while other side is flat. For both sides inlet and outlet are given. The system can facilitate two types of fluid to flow at two sides of membrane for filtration. The membrane thickness achieved was 4 μm. The average pore diameter was 50 nm. The nanopores inside the membrane are highly straight and perpendicular to the surface. The fabricated channel and wall width was 200 µm and 100 µm successively. The pillars in between microchannels hold the membrane which is termed as partial freestanding alumina (PFA) and thereby retain desired mechanical properties of the membrane. The system was tested for diffusion between DI water and salted water. The DI water was flowed in channels and salted water on other side of membrane. The pH value of DI water changed after flow. Due to channel walls, AAO membrane fabricated in this system can tolerate more pressure which leads it to be used for convective flow by applying higher pressure gradient.

Rapid and tunable growth of well-ordered hexagonal nanoporous anodic aluminum oxide (AAO) structure by two step high temperature anodization

2021 ◽  
Author(s):  
Kashif Azher ◽  
Maaz Akhtar ◽  
Shao-Fu Chang ◽  
Shih-Hsun Chen
Keyword(s):  
High Temperature ◽  
Aluminum Oxide ◽  
Anodic Aluminum Oxide ◽  
Pure Aluminum ◽  
Aluminum Substrate ◽  
Nanoporous Structure ◽  
Average Pore ◽  
Cross Sectional ◽  
Anodic Aluminum ◽  
Nano Channel

In this study, we have developed a swift and well-ordered growth of the Anodic Aluminum Oxide (AAO) nanoporous structure by two-step high temperature anodization of pure Aluminum substrate. The pre-anodization surface treatment of the aluminum substrate assists in the formation of well-organized nanoporous structures. The two-step anodization process was performed in 0.3 M of oxalic acid at 20 °C for 40 V and 45 V to obtain tunable pore diameters. The high temperature of the electrolyte solution helps in the rapid growth of the AAO nanoporous structure. The top surface image of AAO shows a well-ordered nanoporous structure with an average pore diameter of 70 nm at 40 V and 100 nm at 45 V. The SEM cross sectional view also illustrates the well-ordered nano channel and the elemental mapping elaborates the presence of aluminum and oxygen. The thickness of the AAO nanoporous structure was determined by using SEM for three anodization time spans (20, 24 and 28 hours), in which an increasing trend was observed. The fabricated AAO has a higher thickness and a well-ordered nanoporous structure that shows it can be used as a template for fabricating nanostructured materials.

Effect of Preparation Conditions on the Performance of Anodic Aluminum Oxide Films

2012 ◽  
Vol 164 ◽  
pp. 223-226
Author(s):  
Xiao Zhen Liu ◽  
Jun Hua Yang ◽  
Gang Wang ◽  
Ling Ling Song ◽  
Ge Shi Zhuang
Keyword(s):  
Acid Solution ◽  
Aluminum Oxide ◽  
Sulphuric Acid ◽  
Anodic Aluminum Oxide ◽  
Sulphuric Acid Solution ◽  
Anodization Voltage ◽  
Anodization Time ◽  
Anodic Aluminum ◽  
Preparation Conditions ◽  
Anodization Method

Neodymium salt was used as additives in preparing anodic aluminum oxide (AAO) films to improve its performance. AAO films were prepared by anodization method from a 15 vol. % sulphuric acid solution containing neodymium salt. The effects of anodization voltage, anodization temperature and anodization time on microhardness and thickness of AAO films were researched, respectively. The thickness of AAO film increases with the increase of anodization voltage, the microhardness of AAO film decreases with the increase of anodization voltage in 19 V～23 V. The thickness of AAO film increases with the increase of anodization temperature, the microhardness of AAO film decreases with the increase of anodization temperature in 11 °C～19°C. The thickness of AAO film increases with the increase of anodization time, the microhardness of AAO film decreases with the increase of anodization time in 30 min～3 h. When the anodizing parameters: anodization voltage: 22 V, temperature: 15°C, anodization time: 2 h, the thickness and microhardness of AAO film is as high as 135μm and 305.4 HV.

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