PHYSICOCHEMICAL CHARACTERIZATION OF CORROSION LAYERS FORMED ON IRON IN A SODIUM CARBONATE-BICARBONATE CONTAINING ENVIRONMENT

Corrosion layers developed on iron in a carbonate-bicarbonate environment in the active-passive potential range have been studied, in relation with Stress Corrosion Cracking (SCC) phenomena, by various physico-chemical techniques: Electrochemical Impedance Spectroscopy (EIS), Infrared Spectrometry (IRS), Scanning Electron Microscopy (SEM) and Energy Dispersive Spectrometry (EDS). The chemical and electrical natures of the corrosion deposits, as well as surface morphologies, have been investigated. The influences of both formation temperature and time have been taken into account.