Experimental and Numerical Studies of Single Manganese Sulfide Inclusions in Stainless Steel During Initiation of Pitting Corrosion

189 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2001.Mathematical modeling was used to simulate the dissolution of a single MnS inclusion within a microelectrochemical cell. The model allowed for the evaluation of the hypothesis of mechanism of pit initiation based a critical concentration of thiosulfate which results in depassivation of the stainless steel. The model supported the view that local acidification occurs after the initiation of pitting rather than trigger initiation. In addition, the model supported the hypothesis that pit initiation occurs due to the accumulation of an aggressive dissolved sulfur species, such as thiosulfate, as a result of inclusion dissolution. Critical pitting potentials were predicted based on a critical thiosulfate concentration and compared to experimentally measured values at single inclusions.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD