Electrochemical study of the pitting corrosion of aluminium and its alloys—III. The role of bonded water and the kinetics of formation and reformation of a passive layer

Abstract Hydrogen evolution and aluminium electrodissolution processes were investigated by cv and coulometric methods on Al electrode at the cathodic end of the polarization curve. The proton or water is reduced at the passive layer with a diffusion controlled rate. The water content of the passive layer on Al was intestigated by a radiotracer technique using tritium labelled water. The water content of passive layers formed by different processes is different. By short-term sorption experiments an oxide layer reformation process was detected; a new (EPDP) model was proposed for the formation of the passive layer on aluminium and indicated by the variation of the pitting potential and the aluminium content of solution.