Figure 6

SEM images of the 24 h dealloyed Zr-Cu-Ag-Al-O ribbon in hydrofluoric acid with different concentrations. (a) Zr-Cu-Ag-Al-O ribbon dealloyed in 0.01 M hydrofluoric acid for 24 h. (b) The enlarged SEM image of (a). (c) Zr-Cu-Ag-Al-O ribbon dealloyed in 0.25 M hydrofluoric acid for 24 h. (d) The enlarged SEM image of (c).