3.3. Microstructure
FE-SEM images clearly displaying the pore structure at the
surface of the porous oxides formed at different temperatures
were captured at high magnifications. Fig. 4a, b and c represent
pictures of the porous anodic oxides formed at electrolyte
temperatures of 5 °C, 35 °C and 55 °C respectively. The surface
of the oxide formed at 5 °C possessed a dense structure with
small pores and separated by thick pore walls, whereas with
increasing electrolyte temperature the structure became more
open with increasing pore diameters and declining wall