Electrochemical Characteristics of Chromium-Saving Ferritic Stainless Steel

Abstract Effects of Al and Si added to Fe-8% Cr alloys on anodic polarization and decay curves obtained in 0.05 M sulfuric acid (H2SO4) aqueous solution were studied to explore the possibility of developing a Cr-saving stainless steel. Experimental results showed that the critical current density for passivation decreased with increasing Al and Si contents in Fe-8% Cr alloys. Combined addition of Al and Si decreased the current density more effectively. Addition of Al had a slight effect in making the decay time longer. However, addition of Si made the decay time exceedingly longer. The pitting potential in 3.5% sodium chloride (NaCl) aqueous solution moved in the noble direction with increasing Al and Si contents. Fe-8% Cr alloys containing Al and Si had the corrosion resistance that was equal to or greater than that of Fe-12% Cr stainless steel.