pH evolution around the AZ31/Steel galvanic couple under gelled-electrolytes: a numerical and experimental study

Abstract This work presents an experimentally validated theoretical model for Mg alloy dissolution that accounts for transport phenomena. The galvanic interaction between AZ31 Mg alloy and low carbon steels in a solid electrolyte was simulated. The use of a solid agar-based electrolyte allowed to neglect the strong convective effects that are normally present during Mg alloy dissolution caused by copious hydrogen evolution. Furthermore, it allowed for a constant electrolyte thickness to be fixed. The gelled-electrolyte contained a pH indicator to permit a reliable visual tracking of the transient propagation of H+ and OH− ions during the electrochemical reaction.