Formation Mechanism Of Porous Anodic Alumina Based On The Barrier Anodic Alumina

The anodic aluminum oxide (AAO) films were produced by anodization while the anodizing process and AAO films were characterized by means of Voltage-time (V-t) curves,SEM.EDAX.Then we present a new growth model for porous anodic alumina membrane (PAAM).First we studied the mechanism of burning and sparking in typical barrier anodic alumina membrane (BAAM) electrolytes through the common characters of V-t curves in different BAAM electrolytes and the effect of pressure on oxygen evolution;then,we added the phosphoric acid solutions of different concentration to typical BAAM electrolytes. The BAAM turned into the PAAM completely with the phosphoric acid solutions of concentration increased. We analyzed the formation of pores in mixed electrolytes.We gave research on the effect of the acidity of electrolytes and the concentration of phosphoric acid on the morphology of PAA. We discussed the formation of PAA in PAAM electrolytes,while we verified the exist of anion-contaminated alumina. With the added reducer,we tested the effect of oxygen bubbles on the shape of pores. Finally,we put forward a new growth model for PAA—oxygen bubble mould effect and the mechanism of PAA and we also gave a new explanation for the V-t curve of anodization.