Initial stages of AZ31B magnesium alloy degradation in ringer’s solution: Interpretation of EIS, mass loss, hydrogen evolution data and scanning electron microscopy observations

Abstract

The initial stages of corrosion of AZ31B magnesium alloy, immersed in Ringer’s solution at 37°C body temperature for four days, have been evaluated by independent gravimetric and chemical methods and through electrochemical impedance spectroscopy (EIS) measurements. The corrosion current densities estimated by hydrogen evolution are in good agreement with the time-integrated reciprocal charge transfer resistance values estimated by EIS. The change in the inductive behavior has been correlated with difference in the chemical composition of corrosion layers. At the shorter immersion of 2 days, EDS analysis of cross section of the uniform corrosion layer detected Cl and Al elements, perhaps as formed aluminum oxychlorides salts.