ON THE GROWTH OF HIGHLY ORDERED PORES IN ANODIZED ALUMINUM-OXIDE

It is now established that hexagonally ordered domain structures can b e formed in anodic alumina films by repeated anodization and stripping of the porous oxide. We find that the domain size is a linear functio n of time and increases with temperature. The pore density is initiall y high but decreases with anodizing time, as dominant pores deepen. Ve ry small pores exist in native oxide in air or nucleate after electrop olishing. Pore growth may start when the electric field increases at t he pore bottoms, and acid dissolves the oxide locally.