0000000000322826
AUTHOR
F. Rechou
The anodic and cathodic dissolution of Al and Al–Cu–Mg alloy
Abstract Atomic emission spectroelectrochemistry (AESEC) was used to monitor the release of Al from 99.99% aluminum (1199 alloy) and Al, Mg, and Cu from 2024 Al alloy in 30 g/l NaCl electrolyte as a function of pH. The cathodic dissolution of Al was demonstrated and attributed to an increase in the pH at the interface due to the water reduction reaction. The dissolution of Mg was also observed but was a more complex function of current probably depending on the interfacial pH and the Al dissolution rate. The detachment of copper-rich particles was observed as very rapid spectroscopic emission transients (peak width
Effect of the surrounding aeration on microcapillary electrochemical cell experiments
In the microelectrochemical capillary cell technique a silicone rubber gasket is used to avoid any electrolyte leakage between the pulled glass capillary and the working electrode (the metallic tested material). In this study, it is demonstrated that the oxygen reduction reaction (ORR) is strongly affected by the use of the silicone rubber. Experiments under a surrounding argon gas shielding of the pulled capillary in contact with the metallic surface have been performed showing a large effect on the ORR. Considering the high permeation rate of oxygen through silicone, the decrease of the reaction rate observed experimentally was validated by FEM modelling assuming that the air/silicone/wat…
Effect of Aeration on the Microelectrochemical Characterization of Al[sub 2]Cu Intermetallic Phases
Local probing of the galvanic coupling between micrometer-sized Al 2 Cu phases and the surrounding aluminum-based matrix of a specially heat-treated 2011 alloy is investigated using a microcapillary electrochemical cell. The aging of an isolated Al 2 Cu particle, i.e., selective dissolution of aluminum, is controlled by the aeration condition at the tip of the capillary due to the nature of the silicon membrane used as a gasket. The local electrochemical behavior of an isolated particle after aging confirms the mass transport control of the oxygen reduction on the galvanic coupling of the particle with the surrounding matrix.
Influence of aeration on the localized trenching on aluminium alloys
This paper aims to make the difference between alcalinisation and micro-galvanic corrosion in the mechanism of the corrosion of Al alloys. Using a pH microprobe, the pH changes inside a pure water droplet deposited on a thermal aged 2011 aluminium alloy were scanned. These pH variations, depending on the position inside the droplet, were related to the heterogeneous corrosion attacks of the aluminium surface quantified by AFM measurements. A modelling investigation is proposed to evaluate the distinct roles of alcalinisation, due to the oxygen reduction reaction (ORR), and the galvanic coupling between intermetallic particles and the surrounding matrix. It can be concluded that the former c…