Metastable Pitting and the Critical Pitting Temperature

摘要: For any particular stainless steel, a critical pitting temperature (CPT) can be measured, below which stable pits do not occur at potential up to the onset of transpassivity. The more highly alloyed particularly with molybdenum, higher CPT. CPT for 904L austenitic steel 240 grit surface finish has been determined as 48 49 C, and metastable events have analyzed in detail lower temperatures. Below CPT, activity peaks around 300 mV (SCE), but occurs all potentials transpassive range. morphology these examined using SEM model is proposed precipitation an anodic salt film within factor; above essential pit growth, while intermediary oxide passivation, like that iron sulfuric acid. This outcome complex dynamical system does require properties itself change suddenly temperature.