SEM images (CBS mode) of the surface of the Al-Si7-Mg0.3 samples after immersion for 1 month in the Adriatic Sea. The sample was sonicated before the analysis. Two distinct areas are recognized: (1′) covered with a thick oxide layer containing Si-rich particles and (2′) covered with a thin oxide layer. Different magnifications are used in (a) and (b). The EDS analysis was made at the numerated sites 1 and  2 in (c), and 3 (b); the results are presented in Table 6. The green rectangle denotes the spot where the FIB cross section was made (Figure 14). SEM and EDS analyses were made at 15 kV. The sample was sonicated before the analysis.