Аннотация:The growth kinetics and chemical composition of the anodic films formed on aluminum in 56% aqueous nitric acid solution were studied by x-ray photoelectron spectroscopy. The anodic films being formed are shown to be porous, hydrated aluminum oxide. Parallel to the electrochemical process, the electrolyte reacts chemically with aluminum during anodic oxide growth, which modifies the oxide growth kinetics and has the effect that molecular nitrogen-containing forms are built into the oxide. The maximum nitrogen concentration in the oxide is attained at the time when the oxide's porous structure is evolved.