scholarly journals Effect of Manganese Content on the Fabrication of Porous Anodic Alumina

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
C. H. Voon ◽  
M. N. Derman ◽  
U. Hashim
Keyword(s):  
Pore Diameter ◽  
Chromic Acid ◽  
Cell Structure ◽  
Manganese Content ◽  
Single Step ◽  
Anodic Alumina ◽  
Porous Anodic Alumina ◽  
Secondary Phases ◽  
Interpore Distance ◽  
Ordered Porous

The influence of manganese content on the formation of well-ordered porous anodic alumina was studied. Porous anodic alumina has been produced on aluminium substrate of different manganese content by single-step anodizing at 50 V in 0.3 M oxalic acid at 15°C for 60 minutes. The well-ordered pore and cell structure was revealed by subjecting the porous anodic alumina to oxide dissolution treatment in a mixture of chromic acid and phosphoric acid. It was found that the manganese content above 1 wt% impaired the regularity of the cell and pore structure significantly, which can be attributed to the presence of secondary phases in the starting material with manganese content above 1 wt%. The pore diameter and interpore distance decreased with the addition of manganese into the substrates. The time variation of current density and the thickness of porous anodic alumina also decreased as a function of the manganese content in the substrates.

Effect of Anodizing Voltage on the Formation of Porous Anodic Alumina on Al-0.5wt% Mn Alloys

2014 ◽  
Vol 925 ◽  
pp. 455-459 ◽  
Author(s):  
Chun Hong Voon ◽  
M.N. Derman ◽  
U. Hashim ◽  
K.L. Foo
Keyword(s):  
Pore Diameter ◽  
Anodic Alumina ◽  
Porous Anodic Alumina ◽  
Manganese Alloy ◽  
Interpore Distance ◽  
Ordered Porous

In this study, the effect of anodizing voltage on the morphologies, pore diameter and interpore distance on the porous anodic alumina formed on aluminium manganese alloy was reported. It was found that the anodizing influenced the morphologies and regularities of porous anodic alumina formed on aluminum-manganese substrate. Well ordered porous anodic alumina was obtained when anodizing voltage were 40 V and 50 V respectively. Disordered porous anodic alumina was formed when anodizing of 30 V and 70 V were applied during the anodizing process. Both pore diameter and interpore distance of porous anodic alumina increased linearly with the anodizing voltage.

Effect of Anodizing Voltage on the Morphology and Growth Kinetics of Porous Anodic Alumina on Al-0.5 wt% Mn Alloys

2013 ◽  
Vol 832 ◽  
pp. 101-106 ◽  
Author(s):  
C.H. Voon ◽  
M.N. Derman ◽  
U. Hashim ◽  
K.L. Foo ◽  
Tijjani Adam
Keyword(s):  
Growth Kinetics ◽  
Pore Diameter ◽  
Dielectric Breakdown ◽  
Anodic Alumina ◽  
Porous Anodic Alumina ◽  
Manganese Alloy ◽  
Interpore Distance ◽  
Dimensional Parameters ◽  
Pore Arrangement ◽  
Kinetics Of

In this study, the effect of anodizing voltage on the morphology of porous anodic alumina and growth kinetics of anodizing of aluminium manganese alloy was reported. It was found that the increasing anodizing voltage affect the morphology and dimensional parameters of porous AAO. Both pore diameter and interpore distance increased as a function of anodizing voltage. The regularity of porous AAO was affected by anodizing voltage. Dielectric breakdown occurred at anodizing voltage of 70 V and led to protrusions and cracks of the porous anodic alumina. Moderate anodizing voltage promoted the formation of well ordered pore arrangement while disordered pore arrangement was observed when the anodizing voltage was too low or too high. The thickness of porous AAO increased as the anodizing voltage increased.

Oxide Dissolution Treatment of Porous Anodic Alumina

2015 ◽  
Vol 1109 ◽  
pp. 73-77
Author(s):  
Chun Hong Voon ◽  
Mohd Nazree Derman ◽  
U. Hashim ◽  
Bee Ying Lim ◽  
Sung Ting Sam
Keyword(s):  
Periodic Structures ◽  
Cell Structure ◽  
Anodic Alumina ◽  
Porous Anodic Alumina ◽  
Hexagonal Cell ◽  
Oxide Dissolution ◽  
Purity Aluminium ◽  
High Purity Aluminium ◽  
Pore Arrangement ◽  
Ordered Porous

In this study, oxide dissolution treatment was used for the formation of well ordered porous anodic alumina. Porous anodic alumina was formed on mechanically polished high purity aluminium by anodizing at 50 V in 0.3 M oxalic acid of 15°C for 60 minutes. It is observed that the pore arrangement of as anodized porous anodic alumina was randomly distributed and showed no ordered hexagonal cell structure. As anodized porous anodic alumina were then subjected to oxide dissolution treatment of increasing exposure duration, up to three minutes. Micrographs were captured by using scanning electron microscope. Pore arrangement of porous anodic alumina subjected to oxide dissolution treatment up to two minutes were similar to one another where no ordered periodic structures were formed. .When porous anodic alumina subjected to oxide dissolution treatment for three minutes, a perfect hexagonal pore arrangement was obtained.

scholarly journals Manufacturing of highly ordered porous anodic alumina with conical pore shape and tunable interpore distance in the range of 550 nm to 650 nm

2017 ◽  
Vol 35 (3) ◽  
pp. 511-518 ◽  
Author(s):  
Małgorzata Norek ◽  
Maksym Łażewski
Keyword(s):  
Citric Acid ◽  
Acid Solution ◽  
Pore Structure ◽  
Anodic Alumina ◽  
Porous Anodic Alumina ◽  
Etidronic Acid ◽  
Acid Electrolyte ◽  
High Concentration ◽  
Interpore Distance ◽  
Ordered Porous

AbstractIn this work, highly ordered porous anodic alumina (PAA) with tapered pore structure and interpore distance (Dc) in the range of 550 nm to 650 nm were fabricated. To produce hexagonal close-packed pore structure a two-step process, combining anodization in etidronic acid electrolyte in the first step and high-concentration, high-temperature anodization in citric acid electrolyte in the second step, was applied. The Al pre-patterned surface obtained in the first anodization was used to produce regular tapered pore arrays by subsequent and alternating anodization in 20 wt.% citric acid solution and pore wall etching in 10 wt.% phosphoric acid solution. The height of the tapered pores was ranging between 2.5 μm and 8.0 μm for the PAA with Dc = 550 nm and Dc = 650 nm, respectively. The geometry of the obtained graded structure can be used for a production of efficient antireflective coatings operating in IR spectral region.

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

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.

Synthesis of Porous Anodic Alumina (PAA) on Aluminum Alloy AA6061 in Mixture of Phosphoric Acid and Oxalic Acid

2016 ◽  
Vol 857 ◽  
pp. 237-241
Author(s):  
Chun Hong Voon ◽  
Bee Ying Lim ◽  
K.L. Foo ◽  
Uda Hashim ◽  
Sung Ting Sam ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Oxalic Acid ◽  
Phosphoric Acid ◽  
Anodic Alumina ◽  
Porous Anodic Alumina ◽  
X Ray Diffraction ◽  
X Ray ◽  
Interpore Distance ◽  
Diffraction Patterns ◽  
Ordered Porous

In this study, porous anodic alumina was formed on aluminum alloy AA6061 by anodizing using mixture of 0.3 M oxalic acid and phosphoric acid with concentration ranged from 0.1 M to 1.0 M. 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 decreased with the increasing concentration of phosphoric acid in the electrolyte. Well-ordered porous anodic alumina was formed in mixture of 0.3 M oxalic acid and 0.1 M phosphoric acid while disordered porous anodic alumina were formed when the concentration of phosphoric acid were in the range of 0.3 M to 1.0 M. Pore size and interpore distance were found to increase with the concentration of phosphoric acid in the mixture. X-ray diffraction patterns show that to γ-Al2O3 were formed on the surface of AA6061 after the anodizing process, regardless of the concentration of phosphoric acid in the mixture electrolyte.

scholarly journals Effect of Temperature of Oxalic Acid on the Fabrication of Porous Anodic Alumina from Al-Mn Alloys

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
C. H. Voon ◽  
M. N. Derman ◽  
U. Hashim ◽  
K. R. Ahmad ◽  
K. L. Foo
Keyword(s):  
Oxalic Acid ◽  
Pore Wall ◽  
Single Step ◽  
Anodic Alumina ◽  
Porous Anodic Alumina ◽  
Effect Of Temperature ◽  
Interpore Distance ◽  
Rate Of Increase ◽  
Steady State Current ◽  
Increasing Temperature

The influence of temperature of oxalic acid on the formation of well-ordered porous anodic alumina on Al-0.5 wt% Mn alloys was studied. Porous anodic alumina has been produced on Al-0.5 wt% Mn substrate by single-step anodising at 50 V in 0.5 M oxalic acid at temperature ranged from 5°C to 25°C for 60 minutes. The steady-state current density increased accordingly with the temperature of oxalic acid. Hexagonal pore arrangement was formed on porous anodic alumina that was formed in oxalic acid of 5, 10 and 15°C while disordered porous anodic alumina was formed in oxalic acid of 20 and 25°C. The temperature of oxalic acid did not affect the pore diameter and interpore distance of porous anodic alumina. Both rate of increase of thickness and oxide mass increased steadily with increasing temperature of oxalic acid, but the current efficiency decreased as the temperature of oxalic acid increased due to enhanced oxide dissolution from pore wall.

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