Surface Modification of Aluminium Alloy by a Silver Nanoparticle-Doped Coating and Examination of Anticorrosion Protection

2020 ◽  
Vol 404 ◽  
pp. 85-92
Author(s):  
Alexandros Prospathopoulos ◽  
Eleni Pavlidou ◽  
Nikolaos Michailidis
Keyword(s):  
Silver Nanoparticles ◽  
Surface Modification ◽  
Aluminium Alloy ◽  
Aluminium Alloys ◽  
Corrosion Behaviour ◽  
Salt Spray ◽  
Chloride Ions ◽  
Anticorrosion Protection ◽  
Seawater Corrosion ◽  
Anticorrosion Properties

Aluminium alloys are among the metals that can be easily passivated, demonstrating notable anticorrosion properties. Under aggressive environments, like in seawater, corrosion may appear though due to presence of chloride ions (pH>8.5) leading to pitting failures. The objectives of the presented research were to examine the possibility of functionalizing the surface of an aluminium alloy through a polydopamine (PDA) layer with homogeneously dispersed silver nanoparticles (AgNPs) and examine the corrosion behaviour of the nanostructured coating. The development of a PDA coating provides a promising approach for immobilization of silver nanoparticles onto AA6061 substrate. Exposure to salt spray for 60 h and assessment of the corrosion status through various methods were applied. Depending on the process parameters for the fabrication of the PDA-AgNPs layer, an enhanced corrosion protection was achieved compared to the undoped with AgNPs film and the uncoated Aluminium alloy.

Effect of severe plastic deformation by ECAP on corrosion behaviour of aluminium alloy AA 7075

2016 ◽  
Vol 81 (2) ◽  
pp. 55-61 ◽  
Author(s):  
M. Ilieva ◽  
R. Radev
Keyword(s):  
Corrosion Resistance ◽  
Aluminium Alloy ◽  
Equal Channel Angular Pressing ◽  
Pitting Corrosion ◽  
Corrosion Behaviour ◽  
Chloride Concentration ◽  
Chloride Ions ◽  
Angular Pressing ◽  
Pitting Corrosion Resistance ◽  
Aa 7075

Purpose: The present study compares the corrosion behaviour of overaged AA 7075 before and after equal channel angular pressing ECAP in two media, containing chlorides, in order to answer the question how grain refinement of aluminium alloys influences their corrosion properties.Design/methodology/approach: The effect of equal channel angular pressing ECAP on corrosion behaviour of aluminium alloy AA 7075 was studied in two water solutions, containing chloride ions: 1) 0.01 M Na2SO4 with addition of 0.01%Cl-, and 2) 3g/l H2O2 and 57g/l NaCl. The changes in electrochemical characteristics, provoked by grain size refinement after equal channel angular pressing ECAP, were found using potentiodynamic polarisation. Steady state potential, corrosion potential, corrosion current density; breakdown (pitting) potential of overaged and deformed by equal channel angular pressing ECAP aluminium alloy AA 7075 were measured.Findings: In the environment with lower chloride concentration equal channel angular pressing ECAP process led to increase in pitting corrosion resistance and in the medium with higher chloride concentration - to decrease in pitting corrosion resistance. That way grain refinement does not demonstrate a uni-directional influence on corrosion resistance of AA 70775.Research limitations/implications: The results suggest the possibility for development of materials having the same chemical composition but with different corrosion resistance to different environments.Originality/value: The paper presents the corrosion behaviour of ultrafine-grained aluminium alloy AA 7075 and the influence of the chloride ions concentration in the corrosion medium on this behaviour.

scholarly journals INVESTIGATION OF THE CORROSION BEHAVIOUR OF ALUMINIUM ALLOY IN SELECTED ENVIRONMENTS

2019 ◽  
Vol 3 ◽  
pp. 92
Author(s):  
Kalina Kamarska
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Rate ◽  
Aluminium Alloy ◽  
Corrosion Behaviour ◽  
Chloride Ions ◽  
Nitrate Ions

The corrosion behaviour of aluminium alloy EN AW-2011 was investigated in selected environments of various electrolytes using gravimetric technique. The results showed that, under the conditions employed in the present work, the corrosion rate of this alloy depends on the specific ions present in solution. The corrosion resistance of aluminium alloy EN AW-2011 is higher in solutions of acids and salts containing sulfate and nitrate ions than in these consisting chloride ions.

Corrosion Behaviour of a Laser-MIG hybrid welding-brazing Joint of 6061 Aluminium Alloy to SUS304 Stainless Steel

CORROSION ◽  
10.5006/3866 ◽  
2021 ◽  
Author(s):  
ruilin liu ◽  
Yunqi Liu ◽  
Zheng Lei ◽  
Hui Tang ◽  
Shaoxiong He ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Weld Metal ◽  
Aluminium Alloy ◽  
Electrochemical Impedance ◽  
Corrosion Behaviour ◽  
Salt Spray ◽  
Chemical Properties ◽  
Open Circuit ◽  
Hybrid Welding

Lightweight steel-aluminium structures have broad application prospects because of their lowering weight characteristics, however, the corrosion of welding-brazing joints in steel-aluminium structures is less concerned or studied. In this paper, the corrosion behaviour of the Laser-MIG hybrid welding-brazing joints of steel-aluminium is investigated through the tests and analysis of salt spray, immersion and electrochemistry. The salt spray and immersion tests show that obvious galvanic corrosion occurs at the welded joints, in which the aluminium side is seriously corroded while the steel side is not corroded. The OCP values of the aluminium alloy and the weld metal are similar (approximately -0.48 V), and the stainless steel has a higher OCP value of -0.33 V. The corrosion resistance of the weld metal is lower than aluminium- as well as steel-base materials. The corrosion resistance of the joints is controlled by the aluminium alloy part of the two metals based on the open-circuit potential and EIS analysis. A possible corrosion process schematic for the physical/chemical properties of a welding-brazing joint immersed in a sodium chloride solution is proposed according to electrochemical impedance spectroscopy.

scholarly journals Mechanical clinching and self-pierce riveting for sheet combination of 780-MPa high-strength steel and aluminium alloy A5052 sheets and durability on salt spray test of joints

2021 ◽  
Vol 113 (1-2) ◽  
pp. 59-72
Author(s):  
Yohei Abe ◽  
Ken-ichiro Mori
Keyword(s):  
Aluminium Alloy ◽  
High Strength Steel ◽  
Salt Spray ◽  
High Strength ◽  
Alloy Sheet ◽  
Galvanized Steel ◽  
Load Reduction ◽  
Minimum Thickness ◽  
Steel Sheets ◽  
Mechanical Clinching

AbstractTo increase the usage of high-strength steel and aluminium alloy sheets for lightweight automobile body panels, the joinability of sheet combinations including a 780-MPa high-strength steel and an aluminium alloy A5052 sheets by mechanical clinching and self-pierce riveting was investigated for different tool shapes in an experiment. All the sheet combinations except for the two steel sheets by self-pierce riveting, i.e., the two steel sheets, the two aluminium alloy sheets, and the steel-aluminium alloy sheets, were successfully joined by both the joining methods without the gaps among the rivet and the sheets. Then, to show the durability of the joined sheets, the corrosion behaviour and the joint strength of the aged sheets by a salt spray test were measured. The corrosion and the load reduction of the clinched and the riveted two aluminium alloy sheets were little. The corrosion of the clinched two steel sheets without the galvanized layer progressed, and then the load after 1176 h decreased by 85%. In the clinched two galvanized steel sheets, the corrosion progress slowed down by 24%. In the clinched steel and aluminium alloy sheets, the thickness reduction occurred near the minimum thickness of the upper sheet and in the upper surface on the edge of the lower aluminium alloy sheet, whereas the top surface of the upper sheet and the upper surface of the lower sheet were mainly corroded in the riveted joint. The load reduction was caused by the two thickness reductions, i.e., the reduction in the minimum thickness of the upper sheet and the reduction in the flange of the aluminium alloy sheet. Although the load of the clinched steel without the galvanized coating layer and aluminium alloy sheets decreased by about 20%, the use of the galvanized steel sheet brought the decrease by about 11%. It was found that the use of the galvanized steel sheets is effective for the decrease of strength reduction due to corrosion.

scholarly journals Homogenisation Efficiency Assessed with Microstructure Analysis and Hardness Measurements in the EN AW 2011 Aluminium Alloy

Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1211
Author(s):  
Maja Vončina ◽  
Aleš Nagode ◽  
Jožef Medved ◽  
Irena Paulin ◽  
Borut Žužek ◽  
...  
Keyword(s):  
Experimental Data ◽  
Image Analysis ◽  
Phase Equilibrium ◽  
Aluminium Alloy ◽  
Phase Formation ◽  
Aluminium Alloys ◽  
Eutectic Phase ◽  
The Matrix ◽  
Equilibrium Solidification ◽  
Homogenisation Process

When extruding the casted rods from EN AW 2011 aluminium alloys, not only their homogenized structure, but also their extrudable properties were significantly influenced by the hardness of the alloy. In this study, the object of investigations was the EN AW 2011 aluminium alloy, and the effect of homogenisation time on hardness was investigated. First, homogenisation was carried out at 520 °C for different times, imitating industrial conditions. After homogenisation, the samples were analysed by hardness measurements and further characterised by microscopy and image analysis to verify the influence of homogenisation on the resulting microstructural constituents. In addition, non-equilibrium solidification was simulated using the program Thermo-Calc and phase formation during solidification was investigated. The homogenisation process enabled more rounded shape of the Al2Cu eutectic phase, equilibrium formation of the phases, and the precipitation in the matrix, leading to a significant increase in the hardness of the EN AW 2011 aluminium alloy. The experimental data revealed a suitable homogenisation time of 4–6 h at a temperature of 520 °C, enabling optimal extrusion properties.

Study on the Formability of Aluminium Alloy Sheets at Room and Elevated Temperatures

2016 ◽  
Vol 877 ◽  
pp. 393-399
Author(s):  
Jia Zhou ◽  
Jun Ping Zhang ◽  
Ming Tu Ma
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Elevated Temperature ◽  
Aluminium Alloy ◽  
Aluminium Alloys ◽  
Elevated Temperatures ◽  
Hot Stamping ◽  
Natural Aging ◽  
Alloy Sheet ◽  
Aluminum Alloy Sheet

This paper presents the main achievements of a research project aimed at investigating the applicability of the hot stamping technology to non heat treatable aluminium alloys of the 5052 H32 and heat treatable aluminium alloys of the 6016 T4P after six months natural aging. The formability and mechanical properties of 5052 H32 and 6016 T4P aluminum alloy sheets after six months natural aging under different temperature conditions were studied, the processing characteristics and potential of the two aluminium alloy at room and elevated temperature were investigated. The results indicated that the 6016 aluminum alloy sheet exhibit better mechanical properties at room temperature. 5052 H32 aluminum alloy sheet shows better formability at elevated temperature, and it has higher potential to increase formability by raising the temperature.

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