fig2
Figure 2. SEM images of iron oxide nanostructures prepared by anodization of Fe foil at 50 V for 1 h using EG electrolytes of various compositions: (A) 0.125 wt.% NH4F and 1.0 vol.% H2O; (B) 0.250 wt.% NH4F and 2.0 vol.% H2O; (C) 0.500 wt.% NH4F and 3.0 vol.% H2O; (D) 1.000 wt.% NH4F and 4.0 vol.% H2O[67]. Reproduced from Ref.[67] with permission from Wiley.
