The process of transition from the active to the passive state by formation of the passivating film. Passivation is achieved by an anodic current which at the respective electrode potential must be larger than the maximum current, or by the presence of an oxidized substance in the neighbouring solution which passivates by being reduced (passivator).
See also: passive state (in electrochemical corrosion), active state (in electrochemical corrosion)
Source:
PAC, 1989, 61, 19. 'Electrochemical corrosion nomenclature (Recommendations 1988)' on page 21 (https://doi.org/10.1351/pac198961010019)