Abstract

Influence of themicrostructure on the corrosion behaviour in a sulphuric solution of cast carbon steels as characterized by electrochemical impedance spectroscopy. Part 2: Effect of the preliminary hardening by compression

Author(s): Manale Belhabib, Patrice Berthod*

In this second part this is in their plastically deformed states that the four carbon steels Fe-xC (x varying from 0 to 1.6 wt.%C) were tested in electrochemical impedance spectroscopy. Performed in the same molar sulphuric solution and following the same procedures, these EIS runs led to Nyquist semi-circles the exploitation of which allowed specifying the evolution of the transfer resistance Rtand of the double layer capacity Cdcwith time during one hour of immersion. All these hardened steels were initially and remain in an active state characterized by low Rt values. Clear dependence of Rt and Cdc on immersion time and on the steel carbon content were highlighted, despite that the deformation ratios were not exactly the same for all steels. However the variations of Rt and Cdc versus the carbon content were inversed by comparison to the results obtained in the first part for the not deformed states. Further investigations must be done to clarify the influence of hardening on these properties, notably by imposing much higher amounts of plastic deformation