Electrochemical Behaviors of Various Alloys in Ferric Sulfate Solution

Abstract

The effects of alloying elements on the electrochemical behaviors in ferric sulfate solution at 25 oC were investigated using A508III low alloy steel, pure Fe, Cr, Ni, 316L SS, 430 SS and Alloy 690. The electrochemical behaviors of A508III steel and iron are similar, showing no active-passivation transition on the anodic polarization curves and no mass-transport-controlled region on the cathodic polarization curves. Active-passivation transition appears on the anodic polarization curves of 316L and 430 steel. Mass-transport-controlled region appears on the cathodic polarization curves of the alloys with certain contents of Cr and Ni. Certain contents of Cr and Ni in alloys increases the open circuit potential, decreases the current density, and increases the electrochemical impedance spectroscopy value. A higher Cr content results in a higher EIS value.