Electrochemical Probes for Metal/Electrolyte System Characterization during Crevice Corrosion

Abstract

Electrochemical microprobes for monitoring of the electrochemical conditions inside recesses are needed to better understand how localized corrosion and other charge-transfer processes occur in confined spaces. The electrode potential distribution can be routinely measured in cavities of greater than 100 μm opening dimension, but the ability to measure the concentrations of chemical species and their change with time in the presence of potential gradients is only recently becoming possible. Microprobes for potential, pH, and chloride ion will be described, and results with these sensors will be presented and discussed for creviced iron samples in aqueous electrolytes. Results reveal that these species change in concentration and distribution with time, with the greatest ionic concentrations corresponding to locations of highest metal dissolution rate on the crevice wall. These new physical chemistry insights provide a better understanding of the passive-to-active behavior in crevices.

On the local corrosion in a thin layer of electrolyte separating two materials: specific aspects and their contribution to pad-to-disk stiction in automobile brake system

“…Indeed, this problem involves the same ingredients as crevice corrosion [9][10][11][12][13], but it cannot be reduced to a crevice since the stiction is strongly dependent on the pad formulation.…”

Chemistry conditions and corrosion behaviour in simulated crevices of alloy steel

“…Knowledge of crevice chemistry is limited by the inability to characterise the dynamic crevice environment [9]. Various techniques that are used to quantify the crevice environment include the use of a syringe [10], capillary electrophoresis [11], freezing and extraction of localised corrosion electrolyte [12] and electrochemical probes [13]. Attempts to model crevice corrosion have had mixed success and there are still some glitches that need to be addressed before achieving a fully predictive, quantitative description of crevice corrosion [14][15][16][17][18].…”

Monitoring the corrosion process of Al alloys through pH induced fluorescence

“…Projections of the cost and safety benefits of corrosion damage monitoring in Europe and the United States have been well documented in the literature [8][9][10]. There have been several attempts to image corrosion by different methods including magnetic measurements [11], potentiometric probing [12], atomic force microscopy [13] and even fluorescence [14,15]. Alodan and Smyrl [16] used confocal laser scanning microscopy in an in situ fluorescence mode to investigate localized corrosion in aluminum alloys in the presence of 0.1 M KCl.…”