Investigation of erosion–corrosion processes using electrochemical noise measurements

This paper presents an example-based discussion of erosion–corrosion and flow corrosion processes that have been identified using electrochemical noise measurements. Various single and dual phase corrosion and erosion–corrosion experiments on austenitic stainless steels and various thermally sprayed coatings using jet impingement and pipe flow rigs are discussed. Localised corrosion events, metastable and propagating pitting, passive and general corrosion processes have been identified under various flow conditions of NaCl solutions. Oscillations in the electrochemical potential noise signals have been related to an erosion-enhanced corrosion synergistic effect. Electrochemical noise measurements show responses to electrolyte permeation of the coating, coating erosion penetration and substrate activity under erosion–corrosion conditions.