Role of a clay sediment deposit on the corrosion of carbon steel in 0.5 mol L−1 NaCl solutions

The role of different minerals (silica, kaolinite, chlorite and montmorillonite) in the corrosion processes of steel in 0.5 mol L−1 NaCl solutions was investigated. About 200–500 μm thick layers of minerals were deposited by sedimentation. Cyclic voltammetry indicated that the deposits favoured a general corrosion process, except montmorillonite that induced a pitting process, explained by the partial dissolution of the particles and their interaction with the steel surface. μ-Raman analyses of the corrosion products found at the steel/deposit interface after 2.5 and 20 h of polarization showed that interactions between minerals and dissolved Fe species could influence rust formation.