Real-time in situ observation of the corrosion process of die-cast AZ91D magnesium alloy in NaCl solutions under galvanostatic polarization

In situ observations of the filiform corrosion process of die-cast AZ91D magnesium alloy were carried out in 0.1 and 0.01 M NaCl solutions (pH 8.0) through a microscale polarization technique. The changes in morphology were observed in real-time using an optical microscope. Filiform corrosion proceeded in lamellar alpha + beta structures adjacent to beta phases and sometimes in the alpha phase grains. The beta phases remained intact after filiform corrosion.