Effect of Ag on cathodic activation and corrosion behaviour of Mg-Mn-Ag alloys

Abstract The effect of Ag on cathodic activation and corrosion behaviour of Mg-Mn-Ag alloys are investigated in the present work. During corrosion, Mg-Ag intermetallic phase undergoes dealloying to form porous Ag-rich remnant whereas Ag in the alloy matrix is dissolved to form Ag+ ions that subsequently redeposit on the alloy surface via displacement reaction with Mg to form Ag nanoparticles, which lead to significant cathodic activation. The cathodic activation is a self-catalysed process since enhanced cathodic activity promotes anodic dissolution which, consequently, results in further enhancement of cathodic activity. Thus, the corrosion rate of Mg-2 Mn-4Ag alloy increases significantly with immersion time.