Corrosion and oxidation behavior of Pr-based bulk metallic glasses

The corrosion behavior of the quaternary Pr–Cu–Ni–Al bulk metallic glasses (BMGs) in 3.5 wt.% NaCl solution were investigated by potentiodynamic polarization and electrochemical impedance spectroscopic techniques. It is found that the there is a good correlation between the corrosion resistance and the glass-forming ability (GFA) in the BMGs, the larger the GFA, the stronger the corrosion resistance. In case of the representative Pr55Cu15Ni15Al16 BMG, the isothermal heat treatment was conducted and it was found that the corrosion resistance became smaller with holding time at 483 K. The thermogravimetry measurement on the Pr–Cu–Ni–Al BMGs showed that the oxidation resistance was deteriorated by increasing the Cu content and no correlations were found with the GFA. The composition of the scales formed during the oxidation was confirmed by X-ray diffraction. The corrosion and oxidation mechanisms were also discussed based on the experimental results.