Fig. 6.

SEM images of (a) Pt- (discs diameter of 4 μm; the space of 4 μm between two nearest platinum discs) and (b) Au-coated (prepared by a quasi-circular template with 200 × 200 μm² size) Fe. Dynamic-potentio polarization curves for (c) Pt- and (d) Au-coated Fe. (e) The corrosion rate values from static immersion tests for 42 days for Pt-coated Fe. (f) Released Fe ion concentration during 30 days immersion test for Au-coated Fe. (a, c, e) Adapted from Ref. [21] copyright 2016, Springer Nature. (b, d, f) Adapted from Ref. [20] copyright 2015, Elsevier.