In situ observation of pitting corrosion of the Zr50Cu40Al10 bulk metallic glass

The polarization behavior of a Zr50Cu40Al10 (atomic percent) bulk metallic glass was investigated in a 0.6 M NaCl electrolyte while being observed using optical microscopy (OM). In situ anodic-polarization experiments revealed a tendency towards a diffusion-controlled mechanism other than passivity. In situ OM images illustrated pits initiated at the corrosion potential (that is, open-circuit conditions). Scanning electron microscopy (SEM) was utilized to examine the region where the corrosion pits initiated. SEM images showed that the area of pit initiation was surrounded by an oxide that formed on the surface due to the exposure to the NaCl electrolyte.