FORMATION OF ANODIC POROUS ALUMINA IN OXALIC ACID AND ELECTRODEPOSITION OF NI.

Nanoporous anodic aluminum oxide (AAO) tubular membranes were fabricated from aluminum alloy tubes in sulfuric and oxalic acid electrolytes using a two-step anodization process. The membranes were investigated for characteristics such as pore size, interpore distance and thickness by varying applied voltage and electrolyte concentration. Morphology of the membranes was examined using light optical and scanning electron microscopy and characterized using Image software. Results showed that membranes having narrow pore size and uniform pore distribution with parallel channel arrays were obtained. The pore sizes were ranging from 10 to 100 nm and the wall thicknesses 60 μm. The catalysts are obtained by impregnation of 3d metals into nanosized pores of aluminum oxide. The obtained catalysts based on nickel and porous Al2O3 are studied by scanning microscopy (SEM-EDX). The results of SEM-EDX analysis shows that a spongy structure with filament sizes of 100 nanometers containing particles of 3d metals formed on the surface of the aluminum oxide matrix.

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Fabrication and Characterization of Highly Ordered Porous Alumina Templates by a Two-Step Anodization Process

Materials Science Forum ◽

10.4028/www.scientific.net/msf.755.75 ◽

2013 ◽

Vol 755 ◽

pp. 75-81

Author(s):

C.A. León-Patiño ◽

E.A. Aguilar-Reyes ◽

C. Ruiz-Aguilar

Keyword(s):

Porous Alumina ◽

Porous Membrane ◽

Interpore Distance ◽

Alumina Membranes ◽

Single Side ◽

Anodic Porous Alumina ◽

20 Nm ◽

Ordered Porous ◽

Through Hole

Highly ordered through-hole anodic porous alumina membranes were fabricated by electrochemical oxidation of aluminum in a controlled two-step process. A teflon dispositive was used to ensure single side anodization. Under the most appropriate condition for the fabrication of ideally ordered anodic aluminum oxide (AAO), the voltage used was 15 V during 24 h in a 15 % w/v sulfuric acid solution. SEM, TEM and FESEM characterization shows that the as-fabricated AAO film has a defect-free array of straight parallel channels perpendicular to the surface. The thickness of the porous membrane is 20 microns, approximately. The ordered channels are formed in a honey comb arrange with a pore diameter in the range 20-30 nm, wall thickness of 10-20 nm, interpore distance of 40 nm, and high aspect ratio of 850. The pore density, quantified by image analysis, is 5.4×1010 pore/cm2; perfect ordering was maintained in the full depth of the membrane. Dimensions of this porous structure provide a convenient way to precision engineer the nanoscale morphology.

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Preparation of Porous Alumina by Anodization

Journal of Metastable and Nanocrystalline Materials ◽

10.4028/www.scientific.net/jmnm.23.75 ◽

2005 ◽

Vol 23 ◽

pp. 75-78 ◽

Cited By ~ 1

Author(s):

C.X. Xu ◽

X.S. Zhang ◽

X.W. Sun

Keyword(s):

Sulfuric Acid ◽

Oxalic Acid ◽

Acid Solution ◽

Sulfuric Acid Solution ◽

Porous Alumina ◽

Fabrication Process ◽

Alumina Films ◽

Anodization Process

The characteristics of porous alumina produced by anodization in both oxalic acid and sulfuric acid solution have been studied. The diameter of the pores for oxalic acid as electrolyte is about 60 nm and for sulfuric acid as electrolyte is about 30 nm. The morphologies of the pores have been improved by two-step anodization process. It has been observed that the temperature and operation voltage are two of the most important factors in the fabrication process of porous alumina films.

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Small-Diameter Magnetic and Metallic Nanowire Arrays Grown in Anodic Porous Alumina Templates Anodized in Selenic Acid

10.21203/rs.3.rs-172696/v1 ◽

2021 ◽

Author(s):

Mahdieh Ahmadzadeh ◽

Mohammad Almasi Kashi ◽

Mohammad Noormohammadi ◽

Abdolali Ramazani

Keyword(s):

Oxalic Acid ◽

Porous Alumina ◽

Small Diameter ◽

Nanowire Arrays ◽

Pore Filling ◽

Selenic Acid ◽

Anodic Porous Alumina ◽

Formation Pattern ◽

20 Nm ◽

Optimized Conditions

Abstract Despite the introduction of selenic acid for anodic porous alumina (APA) preparation with small nanopore diameters (< 20 nm), no attempt has been made to use it in the fabrication of small-diameter magnetic and metallic nanowire arrays. In this paper, considering the high cost of selenic acid, it has been attempted to initially use oxalic acid in preparation of an ordered pattern in the first anodization step, and then employ selenic acid for the second anodization step by matching the appropriate voltage. By investigating the nanopore formation pattern in both acids, it was shown that the nanopores formed in the selenic acid had considerably smaller diameter (13 nm) than that of oxalic acid (35 nm). Under optimized conditions of electrodeposition, various metals were then grown in the selenic APA templates in order to fabricate nanowires with small diameters. The pore filling percentage and crystalline properties were also investigated.

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The Synthesis of Nano-Porous Alumina by Anodization Process

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.781.235 ◽

2015 ◽

Vol 781 ◽

pp. 235-238

Author(s):

Ekarach Jaroonpak ◽

Porntawee Terawan ◽

Naruemon Wannawong ◽

Arkom Kaewrawang ◽

Chaiyaput Kruehong ◽

...

Keyword(s):

Electron Microscope ◽

Oxalic Acid ◽

Pore Diameter ◽

Porous Alumina ◽

Voltage Source ◽

Aluminum Surface ◽

Dc Voltage ◽

Anodization Process ◽

Pore Depth ◽

Scanning Electron

The porous alumina templates were synthesized by anodization process. For preparation, the aluminum foils were cleaned by acetone acid and ethanol. After that, cleaned foils were firstly anodized by oxalic acid with direct current (DC) voltage source. When the first anodization process was complete, the aluminum foils were etched by chromic and phosphoric acid for an hour and then they were secondarily anodized for 15 min to increase the pore depth. For characterization, the surface morphology of porous alumina on aluminum surface was evaluated by scanning electron microscope. The results show that the pore diameter increases with increasing DC voltage and concentration of oxalic acid. The lowest pore diameter is 57.19 nm at DC voltage of 20 V for concentration of 0.2 M that it has highest pores density of 157 Gpores/in2.

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Effect of Concentration of Oxalic Acid on the Synthesis of Porous Anodic Alumina (PAA) on Aluminum Alloy AA6061

Materials Science Forum ◽

10.4028/www.scientific.net/msf.857.281 ◽

2016 ◽

Vol 857 ◽

pp. 281-285

Author(s):

Chun Hong Voon ◽

Bee Ying Lim ◽

K.L. Foo ◽

Uda Hashim ◽

Sung Ting Sam ◽

...

Keyword(s):

Aluminum Alloy ◽

Oxalic Acid ◽

Pore Size ◽

Anodic Alumina ◽

Porous Anodic Alumina ◽

Edx Analysis ◽

Interpore Distance ◽

Ordered Porous

In this study, porous anodic alumina was formed by anodizing of aluminum alloy AA6061 in oxalic acid with concentration ranged from 0.1 M to 1.0 M respectively. AA6061 alloys were anodized at 40 V and 25°C for 60 minutes. FESEM images show that the uniformity of the pores arrangement of porous anodic alumina depends significantly on the concentration of oxalic acid. Well-ordered porous anodic alumina was formed in oxalic acid of 0.3 M, 0.5 M and 0.7 M while disordered porous anodic alumina were formed when the oxalic acid of 0.1 M and 1.0 M were used as electrolytes. EDX analysis revealed that the only peaks corresponding to aluminum and oxygen were detected. Pore size was found to increase with the concentration of oxalic acid while the interpore distance remained almost unchanged although the concentration of oxalic acid increased from 0.1 M to 0.7 M. Atypical anodic alumina without pores arrangement was formed when 1.0 M oxalic acid was used for anodizing.

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Nanostructure of the nanopores in anodic aluminum oxide films used as template to fabricate Ag nanowires

Journal of Materials Research ◽

10.1557/jmr.2009.0206 ◽

2009 ◽

Vol 24 (5) ◽

pp. 1735-1740 ◽

Cited By ~ 9

Author(s):

Junping Zhang ◽

Jerrold E. Kielbasa ◽

David L. Carroll

Keyword(s):

Aluminum Oxide ◽

Barrier Layer ◽

Anodic Aluminum Oxide ◽

Silver Nanowires ◽

Aao Template ◽

Anodic Aluminum ◽

Anodization Process ◽

Nanoporous Anodic Aluminum Oxide ◽

Aluminum Substrates ◽

Nanoporous Anodic Aluminum

Well-ordered nanoporous anodic aluminum oxide (AAO) templates have been prepared on aluminum substrates by a two-step anodization process. A voltage-controlled branching method was successfully used to thin the barrier layer of the AAO template. The nanostructures of the pores, the branched subpores, and the barrier layer in the AAO template were studied in association with the anodization process and barrier layer thinning methods. Results demonstrate the voltage-controlled branching method is a facile and effective way to thin the barrier layer. Uniform silver nanowires can be easily fabricated using alternating current (ac) electrodeposition into the pores of AAO after redressing the barrier layer.

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CRYSTALLIZATION OF ANODIC ALUMINUM OXIDE MEMBRANES

Modern Physics Letters B ◽

10.1142/s0217984909021557 ◽

2009 ◽

Vol 23 (29) ◽

pp. 3497-3501 ◽

Cited By ~ 1

Author(s):

SONG YUE ◽

JUAN DU ◽

YUAN ZHANG ◽

DAPENG CHEN

Keyword(s):

Aluminum Oxide ◽

Anodic Aluminum Oxide ◽

Annealing Treatment ◽

X Ray Diffraction ◽

X Ray ◽

Structure And Morphology ◽

Anodic Aluminum ◽

Anodization Process ◽

Nanoporous Anodic Aluminum Oxide ◽

Oxide Membranes

Nanoporous anodic aluminum oxide membranes (AAM) were fabricated in oxalic acid electrolytes using a two-step anodization process. Membranes' structure and morphology were examined using scanning electron microscopy and X-ray diffraction after the annealing treatment. It was found that the crystallization temperature of the AAM are greatly dependent on their thickness. Aluminum is maintained under the protection of AAM even at 1100°C when the AAM's melting manifests.

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Patterning Anodic Porous Alumina with Resist Developers for Patterned Nanowire Formation

MRS Proceedings ◽

10.1557/opl.2015.566 ◽

2015 ◽

Vol 1785 ◽

pp. 13-18 ◽

Cited By ~ 1

Author(s):

SeungYeon. Lee ◽

Daniel Wratkowski ◽

Jeong-Hyun Cho

Keyword(s):

Silicon Nanowires ◽

Porous Alumina ◽

Chemical Vapor ◽

Initial Step ◽

Metal Substrate ◽

Nanowire Arrays ◽

Anodic Porous Alumina ◽

Anodization Process ◽

Vertically Aligned ◽

Al Thin Film

ABSTRACTFormation of patterned metal and semiconductor (e.g. silicon) nanowires is achieved using anodic aluminum oxide (AAO) templates with porous structures of different heights resulting from an initial step difference made by etching the aluminum (Al) thin film with a photoresist developer prior to the anodization process. This approach allows for the growth of vertically aligned nanowire arrays on a metal substrate, instead of an oriented semiconductor substrate, using an electroplating or a chemical vapor deposition (CVD) process. The vertically aligned metal and semiconductor nanowires defined on a metal substrate could be applied to the realization of vertical 3D transistors, field emission devices, or nano-micro sensors for biological applications.

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