Metastable Pitting of Stainless Steel

Abstract

Current transients resulting from metastable pitting events on stainless steel at potentials below the pitting potential are studied. Metastable pits are covered during growth and exhibit a constant current density. Rupture of the cover during metastable growth leads to repassivation of the pit. If a salt film precipitates on the pit surface before the cover ruptures, pit growth is stabilized. The kinetic factors hindering the replacement of a passive film by a salt film are discussed.