https://doi.org/10.1351/goldbook.P04447
The passive state is characterized by a contiguous 'passivating @[email protected]' of solid @[email protected] products separating the metallic phase from the adjacent electrolyte. @[email protected] in the passive state involves growth of the passivating @[email protected] and/or transfer of metal ions through the @[email protected] into the electrolyte.