Formation of Nanoporous Tin Oxide Layers on Different Substrates during Anodic Oxidation in Oxalic Acid Electrolyte

Figure 9

FE-SEM images of nanoporous tin oxide layers formed during one-step anodizing of Sn wire in 0.3 M oxalic acid at 6 V. The duration of anodization was 5 min (a), 15 min (b, e), and 30 min ((c): “outer” layer, (d): “inner” layer, and (f)).

(a)

(b)

(c)

(d)

(e)

(f)