A. Mozalev et al., The voltage-time behaviour for porous anodizing of aluminium in a fluoride-containing oxalic acid electrolyte, ELECTROCH C, 3(6), 2001, pp. 299-305
A systematic investigation has been undertaken of voltage-time behaviour fo
r galvanostatic porous anodizing of aluminium in 0.4 mol dm(-3) H2C2O4 modi
fied by the addition of variable amounts of NH4F. in circumstances of varyi
ng current density and stirring conditions. Both the concentration of NH4F
in the electrolyte and stirring of the fluoride-containing (FC) electrolyte
appeared to affect the voltage-time response for anodizing aluminium, caus
ing a dl:crease in the forming voltage. The voltage-reducing effect is furt
her substantially enhanced while the solution is stirred. Despite a I:enfol
d decrease in the anodizing voltage in the FC electrolyte, no apparent chan
ges in pore morphology are determined from SEM observation. The phenomena d
escribed are explained by considering formation of FC electrolyte-derived s
pecies and their incorporation into growing oxide film. (C) 2001 Published
by Elsevier Science B.V.