PERFORATED COVERS FOR PROPAGATING PITS

Corrosion pits on stainless steel often grow in such a way as to under mine the original surface, and, consequently, a thin layer of metal an d oxide is left over the growing pit cavity. These pit covers develop a porous, lacelike structure, and a model for the development of this structure is described. Calculations based on this model produce pit m orphologies showing the main features of real pits observed in the sca nning electron microscope and also produce theoretical current transie nts resembling those recorded experimentally.