Electrochemical corrosion behavior of a Zr-based bulk-metallic glass

Using cyclic-anodic-polarization tests, the corrosion behaviors of the as-cast, deformed, and relaxed Zr52.5Cu17.9Ni14.6Al10.0Ti5.0 bulk-metallic glasses were investigated. Their corrosion behaviors are related to the amount of free volume. As the free volume decreased, the glasses became more corrosion resistant. The as-cast and the deformed glasses are less resistant to pit propagation, while the relaxed one is more vulnerable to pit nucleation. It is thought that an increase in free volume favors the pit propagation, and the chemical ordering caused by the relaxation may promote the pit nucleation.