| Melt-spun amorphous-nanocrystalline Mg50Ni30Y20 samples were subjected to chemical pre-treatments in 1% HF and in 10 mg/l YCl3/ 1% H2O2 solution. Their electrochemical behavior in the as-quenched state and after hydrogen charging at -5 mA/cm2 for 20 hours was studied in 6 M KOH, pH=14,8, by means of potentiodynamic polarisation measurements. A pre-treatment with HF solution can improve their anodic passivation behavior by inhibiting a preferential nickel oxidation-dissolution at low polarisation, whereas a YCl3/ H2O2 solution treatment has the opposite effect. Both pre-treatment methods lead to an enhancement of cathodically induced surface degradation processes. |
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