Figure 2.
Scanning electron microscopy (SEM) images of the Ti–O–Cu nanotubular oxide film (Ti–O–CuNT) grown on a Ti–5.5Cu (at. %) alloy substrate by electrochemical anodization and annealed at 450 °C. (A) Top view showing the nanotube structure. (B) Cross-section illustrating the film thickness and nanotube architecture.