SEM images (CBS mode) of the surface of the Al-Si9-Cu3 sample after immersion for 1 month in the Adriatic Sea and lower and higher magnifications. The site where EDS analysis was made is denoted by a green circle in (a) and enlarged in (c). Enlarged detail of the oxide layer is presented in (b). EDS results at sites 1 to 4 are presented in Table 5. The sample was sonicated before the analysis.