Effect of alloying addition of Pr on the dissolution rate of melt-spun Mg in 3% NaCl solution

Melt-spun Mg-1 and 15 wt% Pr binary alloys were immersed in a 3% NaCl solution saturated with Mg(OH)₂ for up to 72 h. The dissolution rate was evaluated by hydrogen evolution method. Surface characterization of the pristine and corroded surfaces has been carried out using X-ray photoelectron spectroscopy (XPS), secondary ion mass spectroscopy (SIMS), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The surfaces of both the pristine and corroded samples were found to consist mainly of Mg(OH)₂ and MgO. However, results of XRD and SEM showed that the dominant product formed on the corroded sample was Mg(OH)₂. SIMS depth profiling showed that there was a depletion of Pr at the surfaces of Mg-Pr samples.