Electrochemical Corrosion of Magnesium Alloy AZ31 in NaCl Solutions After Rolling

The purpose of this study was to evaluate the electrochemical corrosion resistance of magnesium alloy AZ31 after rolling. Corrosion tests were conducted in NaCl solutions containing various concentrations of chloride ions (0.01-2 M NaCl). Potentiodynamic tests were conducted to obtain anodic polarisation curves. Immersion tests were conducted over periods of 1-5 days. The microstructure of AZ31 was examined by scanning electron microscopy (SEM) after the immersion tests. Electrochemical impedance spectroscopy (EIS) was applied to evaluate the electrochemical phenomena occurring at the surface of the tested alloy. Geometrical features of the AZ31 alloy surface were also measured after the corrosion tests. The results of all of the tests carried out demonstrate a clear deterioration in the corrosion properties of magnesium alloy AZ31 with the increase in the molar concentration of the NaCl solution. Irrespective of the molar concentration of the NaCl solution, pitting corrosion on the surface of the tested alloy was observed.