The subject of this article is control of perforated pit growth in 316L stainless steel by application of an artificial overlayer film. The protection afforded by 250 nm thick films with two ZrO2-Al2O3 nanolaminate architectures, single-layer ZrO2, and single-layer Al2O3 under cyclic polarization in saline. electrolyte is reported here. The post-exposure morphology is characterized by scanning electron microscopy with in situ electron energy dispersive spectroscopy. The films' diverse behavior is analyzed in terms of a model for perforated pit growth that requires partial pit occlusion until an autocatalytic geometry is established. The results show that the key property a film must have to arrest the development of autocatalytic geometry is the capability to fracture locally so that the electrolyte from the pit freely mixes with the bulk electrolyte and the pit interior becomes passivated. We show how a nanolaminate with 5.0 nm tetragonal ZrO2-5.0 nm amorphous Al2O3 bilayers sustains local fracture (blow holes) without widespread cracking and is protective against perforated pit growth. (C) 2004 American Vacuum Society.