Fig 4. The degradation surface morphology after 14 days of immersion for pure Mg, Mg-2Ag and Mg-10Gd.

The figures obtained before and after chromic acid treatment (CA). The black spots on top of each sample are markers to define a coordinated position. Scale bars on these optical microscopic images represent 1 mm. Areas of interests were defined in white frames for further inspection under SEM, where the scale bar on these images represents 200 μm.