The effect of hydrodynamics on the corrosion of Al – 14 wt% Zn – 8 wt% Mg alloy in artificial seawater media at room temperature was studied in a rotating cylinder electrode, RCE, system under turbulent flow conditions. Five different rotation rates were studied: 0 (or stagnant conditions), 1000, 3000, 5000 and 7000 rpm. The corrosion rates were measured by electrochemical impedance spectroscopy (EIS).

For the system studied, corrosion potential, Ecorr becomes more positive with increasing of the rotation rate of RCE (Reynolds number, Re). The effect of increasing the Re number is to enhance the availability of oxygen at the electrode surface, which in turn will polarize the corrosion reaction in the more noble direction.

It was found that under turbulent flow conditions, the corrosion rate of Al-alloy linearly increases as the RCE’s rotation rate also increase and the overall electrochemical corrosion process is influenced by the oxygen mass transfer process on the cathodic kinetics.

Subject
Electrochemical impedance spectroscopy, Corrosion rate, Microstructure, Diffusion, Turbulent flow, Cathodic polarization curves, Hydrodynamics, Mass transfer, Ingots, Risk reduction, Alloys, Electrodes, Corrosion potential
Keywords:
aluminum alloy, flow, galvanic anode, mass transfer, rotating cylinder electrode, seawater
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2008
Association for Materials Protection and Performance (AMPP)
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