Journal of Materials Research and Technology Journal of Materials Research and Technology
J Mater Res Technol 2018;7:149-57 DOI: 10.1016/j.jmrt.2017.06.004
Original Article
Role of turbulent flow seawater in the corrosion enhancement of an Al–Zn–Mg alloy: an electrochemical impedance spectroscopy (EIS) analysis of oxygen reduction reaction (ORR)
Marcela C. Quevedo, Gonzalo Galicia, Rodrigo Mayen-Mondragon, Juan Genesca Llongueras,,
Departamento Ingenieria Metalurgica, Facultad Quimica, Universidad Nacional Autonoma de Mexico (UNAM), Ciudad Universitaria, 04510 Ciudad de Mexico, Mexico
Received 20 March 2017, Accepted 01 June 2017
Abstract

The effect of flow on the corrosion of Al–14wt% Zn–8wt% Mg alloy in aerated synthetic seawater at ambient temperature was studied using a rotating cylinder electrode (RCE) under turbulent regime conditions by means of electrochemical impedance spectroscopy (EIS). The overall electrochemical corrosion process was found to be strongly influenced by the oxygen mass transfer process under turbulent flow conditions on the cathodic kinetics, driving to a significant increase in corrosion rate.

At corrosion potential, Ecorr value, contributions from the anodic and cathodic processes involved were observed in the impedance diagrams. Instead, at a cathodic potential of −1.2V (sce), impedance measurements proved the predominance of the mass-transfer process for oxygen. A primary analysis of the impedance plots allowed to confirm such situation.

Keywords
Aluminum alloy, Corrosion, EIS, Flow, Oxygen, Mass transfer, Rotating cylinder electrode, Seawater
J Mater Res Technol 2018;7:149-57 DOI: 10.1016/j.jmrt.2017.06.004