Corrosion Studies of Hf 64 Cu 18 Ni 18 Metallic Glass in Acidic and Alkaline Media

In the present paper, the corrosion behavior of Hf-rich Hf64Cu18Ni18 (at%) metallic glass (MG) was studied in acidic and alkaline media using electrochemical polarization experiments. Three different molar solutions of NaOH and HCl were used for the experiments. The results show that the glassy alloy possesses significantly high corrosion resistance in alkaline solution than acidic one. Pits are observed on the sample in acidic media, whereas alkaline sample does not show pitting. In both the solutions, primarily, HfO2 is formed on the surface as a corrosion product. The corroded surface is non-uniformly distributed on the ribbon and found to decrease with concentration of NaOH. The non-uniform distribution is attributed to inhomogeneity in the ribbon sample. In case of HCl solution, corroded surface increases with the increase in HCl concentration. Furthermore, an attempt has been made to understand the corrosion mechanism of this MG in view of phases formed during the experiment.