EFFECT OF Y AND Nd ADDITION ON THE CORROSION BEHAVIOUR OF AMORPHOUS Mg-Cu AND Mg-Ni ALLOY

The corrosion behaviour, as investigated using hydrogen evolution testing in 3% NaCl (0.51M) solution and using electrochemical techniques in 0.01M NaCl solution has been determined for melt-spun amorphous Mg alloy ribbons containing 21 at% Cu and 18 at% Ni addition with and without ternary addition of Y and Nd. The results show that both the addition of Cu and Ni to pure Mg caused the corrosion rate to increase. Ternary addition of Y and Nd to Mg-Cu and Mg-Ni respectively reduce the corrosion rate of both the alloys. XPS depth profiling shows that Nd was present from the surface to the bulk of the ternary alloy and it reduced the Cl^- content significantly compared to the binary alloy. The results are discussed in the context of other reported observations on the corrosion behaviour of rapidly solidified Mg-based alloys.