Electrochemical potential noise measurements have been used to investigate the initiation and development of crevice corrosion on type 304L stainless steel when immersed in a 0.05 M ferric chloride solution. The spontaneous potential noise fluctuations were recorded in a freely corroding system with respect to a Ag/AgCl reference electrode. The surface activity of the stainless steel was simultaneously studied using a scanning vibrating electrode technique to provide corroborating evidence of the initiation and maintenance of crevice corrosion. Analysis
procedures have included the determination of power spectral densities calculated by fast Fourier transforms, and a stochastic technique based on a Poisson-process test, both were undertaken in an effort to reveal fundamental characteristics of the potential fluctuations resulting from the initiation and propagation of crevice corrosion. The results indicate a correlation between the two analysis methods, both revealed the presence within the time series of stochastic and deterministic features. It was possible to identify the different corrosion processes occurring on the 304L stainless steel, which included: metastable pitting, propagation and termination of localized corrosion events, and the development of crevice corrosion. Keywords: electrochemical potential noise, crevice corrosion, PSD gradients, Poisson-process test, stainless steel.