What activates the Mg surface-A comparison of Mg dissolution mechanisms

Several mechanisms have been proposed to interpret the widely reported phenomenon of Mg corrosion that the hydrogen evolution rate increases with increasing anodic potential or anodic current density. This paper critically analyzed the two main mechanisms, (1) "the incomplete film univalent Mg" ion mechanism" and (2) "the enhanced catalytic activity mechanism", aiming to clarify the current understanding of the Mg corrosion mechanism and to provide a profound insight into the Mg characteristic electrochemical behavior, anodic polarization accelerating both hydrogen evolution and Mg dissolution. It is expected that the deepened fundamental understanding from this comprehensive mechanistic review will provide a basis of practical applications for Mg alloys and open up a new way to the control of corrosion of Mg alloys in practice. (C) 2020 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.