Pitting corrosion, stainless steels depassivation

Pits form grooves or furrows on wall surfaces on stainless steels (Figs. 7.5 and 7.6). Contents leak out of pit interiors and depassivate areas immediately below the active corrosion sites. Grooves form, fol-... 

Interest in the use of these alloys as reinforcements for concrete stems from their greater resistance to chloride induced corrosion. Thus they exhibit a higher pitting potential than plain carbon steel and as a consequence the chloride content required to depassivate the stainless steels is much... 

Fundamentals of the pitting mechanisms have been discussed in Chapter 7 and the whole question of pitting corrosion was reviewed by Smialowska [la] in 1986. It is intended here to shed light on some points of practical or theoretical importance which were recently investigated or revisited and to propose a comprehensive viewpoint on some rather scattered experimental evidence. The examples are restricted to stainless steels, in weakly acid chloride-containing aqueous media whose pH is larger than the depassivation pH, so that the passive film remains stable except in the pit itself. 

---