KINETICS OF FORMATION OF PASSIVE LAYER ON ALUMINUM

Formation of passive layer on aluminium was investigated in aqueous me dia by tritium radiotracer, ICP and electrochemical methods. The triti cum and aluminium contrations in the solutions as well as the critical pitting potential (E(pi)) of aluminium species change similarly in al ternative direction during passivation. The passive layer formation ca n be described by the ''electrochemical dissolution - precipitation - dissolution - precipitation'' (E.P.D.P.) model. The new model is in ac cordance with the obtained experimental results and allows to clarify the debated phenomena published in the literature.