SRET Evaluation of the Corrosion Behavior of Thixocast AZ91 Magnesium Alloy in Dilute NaCl Solution at Room Temperature

Abstract

This work is aimed at examining the corrosion behavior of thixocast (TC) and die cast (DC) AZ91 alloy in dilute chloride solution using scanning reference electrode technique (SRET). The results showed that the as cast skins of TC and DC AZ91 alloy had much higher QEMF values than the bulk samples. The maximum local anode currents (MLAC) of the skins were much higher than those of the bulks. Both the skin and bulk of TC AZ91 alloy were more corrosion resistant than those of DC AZ91 alloy in this medium. The SRET results in 0.014 M NaCl were consistent with those obtained by electrochemical impedance spectroscopy (EIS) in 0.003 and 0.885 M NaCl solutions.