Ja. Wharton et al., Crevice corrosion studies using electrochemical noise measurements and a scanning electrode technique, J ELCHEM SO, 147(9), 2000, pp. 3294-3301
The formation of crevice corrosion on type 304L stainless steel when immers
ed in 0.05 M ferric chloride solution has been used to investigate electroc
hemical potential noise measurements. The surface activity of the stainless
steel was simultaneously studied using a scanning electrode technique to p
rovide corroborating evidence of crevice corrosion. The spontaneous potenti
al noise fluctuations were recorded in a freely corroding system with respe
ct to a reference electrode. Power spectral densities calculated by fast Fo
urier transforms and a stochastic technique were used for the analysis of t
he time records, in order to reveal fundamental characteristics of the fluc
tuations resulting from the initiation and propagation of crevice corrosion
. A stochastic analysis tool based on a Poisson-process test has been devel
oped and evaluated using data generated by computer simulation of both stoc
hastic and deterministic processes, before applying the analysis technique
to real corrosion processes. There appears to be agreement between the two
analysis methods; both revealed the presence within the time series of stoc
hastic and deterministic features. Using a combination of noise analysis te
chniques it was possible to obtain evidence of the different corrosion proc
esses occurring on the 304L stainless steel which were metastable pitting,
propagation and termination of localized corrosion events, and the developm
ent of crevice corrosion. (C) 2000 The Electrochemical Society. S0013-4651(
99)08-125-2. All rights reserved.