Effects of crystallization on corrosion behaviours of a Ni-based bulk metallic glass

The effects of microstructure change on the corrosion behaviours of Ni55Nb20Ti10Zr8Co7 bulk glass-forming alloy were investigated in 1 mol/L HCl and 0.5 mol/L H2SO4 solutions. Different microstructures of the Ni-based alloy were achieved by annealing the bulk glassy rod prepared by copper mould casting. The microstructure, grain size, grain distribution, and phase composition were characterized. Electrochemical behaviours of the Ni-based alloy were revealed by static immersion and anodic potentiodynamic polarization tests. It is indicated that the corrosion behaviours of the Ni-based bulk glass-forming alloy are related to its microstructures, while the fully crystallized alloy exhibits a relatively lower corrosion resistance than those of the amorphous states.