Preparation of TiO₂ Nanotube Array on the Pure Titanium Surface by Anodization Method and Its Hydrophilicity

Figure 2

SEM images of the nanotube arrays anodized at 20 V for different times: (a) 3 h, (b) 6 h, (c) 12 h, and (d) 18 h.

(a)

(b)

(c)

(d)