CORROSION OF A CARBON STEEL COVERED BY TREATED BENTONITES IN AQUEOUS SOLUTION

Abstract

In the present work we realised an electrochemical system for steel/clay/aqueous solutions study. Two Algerian bentonites have been considered. The obtained results show that both clays are corrosive even in the absence of chloride ions. We show that this corrosiveness is related to the cationic exchange capacity (CEC). The chemical treatment of clays by tungstate reduces significantly their CEC and corrosiveness. Electrochemical impedance spectroscopy results prove that tungstate reduce iron and chlorides ions transport through the clay. This deduction is supported also by microscopic observations.