The process of transition from the passive to the active state by removal of the passivating
film. A necessary condition for
activation is an
electrode potential negative to the equilibrium potential of formation of the passivating
film.
Activation is achieved by cathodic currents, by a reduced substance in the adjacent solution, or by contact with an electronic conductor having a suitably negative
corrosion potential.
Source:
PAC, 1989, 61, 19
(Electrochemical corrosion nomenclature (Recommendations 1988))
on page 21