Formation and tribological properties of MoS2 self-lubricating porous anodic alumina thin flims

2019 ◽  
Vol 34 (01n03) ◽  
pp. 2040021
Author(s):  
Dengquan Han ◽  
Yao Wang ◽  
Yuanxing Li ◽  
Xiaoya Li ◽  
Zongtao Zhu ◽  
...  
Keyword(s):  
Solution Concentration ◽  
Anodic Alumina ◽  
Porous Anodic Alumina ◽  
New Approach ◽  
Lubrication Film ◽  
Interpore Distance ◽  
The Coefficient Of Friction ◽  
Disk Friction ◽  
Thin Flims ◽  
Aluminum Plates

MoS2 self-lubricating films were prepared on long-range ordered porous anodic alumina (PAA) by an electrophoretic deposition (EPD) method. The PAA was prepared by two-step anodization of aluminum plates. Oxalic-acid-based electrolytes were used in the first step and phosphoric-acid-based electrolytes were used in the second step. This process offers a new approach to preparing PAA with wide adjustable boundary distances (43.5–21 nm) by increasing the voltage from 80 V to 100 V. The boundary distances were decreased from 78 nm to 42.2 nm by increasing the solution concentration, which increased the interpore distance. The coefficient of friction and hard-wearing of the MoS2 lubrication film on the PAA were studied by a ball-on-disk friction and wear tester. The results showed that the nanotubes stored MoS2 particles, which provided continuous lubrication.

Formation of Porous Anodic Alumina from Impure Aluminum Foil in Inorganic Acids

2015 ◽  
Vol 1112 ◽  
pp. 89-93
Author(s):  
Ahmad Nurrudin ◽  
Brian Yuliarto ◽  
Suyatman ◽  
Agung Sriwongo
Keyword(s):  
Room Temperature ◽  
Porous Alumina ◽  
Aluminum Foil ◽  
Average Diameter ◽  
Anodic Alumina ◽  
Porous Anodic Alumina ◽  
Sulfate Electrolyte ◽  
Average Pore ◽  
Interpore Distance ◽  
Inorganic Acids

The morphology of porous anodic alumina (PAA) formed by anodizing in inorganic electrolytes is reported. An impure aluminum was anodized in sulfuric acid, phosphoric acid and chromic acidat room temperature with a constant applied potential 2 – 30 V. The formation of porous anodic alumina was carried out by one and two steps anodization. It is clearly noted that anodizing impure aluminum at room temperature provide higher kinetic of oxide dissolution compared to oxide growth. Two steps anodizing aluminum in sulfate electrolyte always resulted in random porous alumina, while phosphate electrolyte provided strong anodization producing irregular porous alumina with average diameter of 61.6 nm. Two steps anodizing aluminum in chromate electrolyte produce better pore ordering with relatively large size pore distributions. The average pore diameter of alumina increases linearly with applied voltage, with proportionality factor lp 0.83 nmV-1. Annealing the sample increased the interpore distance, removed stresses providing lower activation energy for pore formation.

scholarly journals A Novel Method for Fabricating Double Layers Porous Anodic Alumina in Phosphoric/Oxalic Acid Solution and Oxalic Acid Solution

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Yanfang Xu ◽  
Xiaojiu Li ◽  
Hao Liu ◽  
Jie Xu
Keyword(s):  
Oxalic Acid ◽  
Acid Solution ◽  
Oxalic Acid Solution ◽  
Anodic Alumina ◽  
Porous Anodic Alumina ◽  
Double Layers ◽  
Pore Density ◽  
Interpore Distance ◽  
Small Pore ◽  
Novel Method

A novel method for fabricating ordered double layers porous anodic alumina (DL-PAA) with controllable nanopore size was presented. Highly ordered large pore layer with interpore distance of 480 nm was fabricated in phosphoric acid solution with oxalic acid addition at the potential of 195 V and the small pore layer was fabricated in oxalic acid solution at the potential from 60 to 100 V. Experimental results show that the thickness of large pore layer is linearly correlative with anodizing time, and pore diameter is linearly correlative with pore widening time. When the anodizing potential in oxalic acid solution was adjusted from 60 to 100 V, the small pore layers with continuously tunable interpore distance from 142 to 241 nm and pore density from1.94×109to4.89×109 cm−2were obtained. And the interpore distance and the pore density of small pore layers are closely correlative with the anodizing potential. The fabricated DL-PAA templates can be widely utilized for fabrication of ordered nanomaterials, such as superhydrophobic or gecko-inspired adhesive materials and metal or semiconductor nanowires.

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.

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.

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.

Small-angle X-ray scattering (SAXS) study of porous anodic alumina—A new approach

2011 ◽  
Vol 131 (1-2) ◽  
pp. 362-369 ◽  
Author(s):  
Abdul Waheed ◽  
Mazhar Mehmood ◽  
Robert Benfield ◽  
Jamil Ahmad ◽  
Heinz Amenitsch ◽  
...  
Keyword(s):  
Small Angle ◽  
Anodic Alumina ◽  
Porous Anodic Alumina ◽  
New Approach ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

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.

Sign in / Sign up

Export Citation Format

Share Document