901076.fig.004a
(a)
901076.fig.004b
(b)
901076.fig.004c
(c)
Figure 4: AFM images (scan area of 2 μm × 2 μm) of ZrO2 surface with different annealing treatment times: (a) 0 min, (b) 15 min, and (c) 60 min.