Electrochemical characteristics of chromium-saving ferritic stainless steel

Effects of Al and Si added to Fe-8% Cr alloys on anodic polarization and de cay curves obtained in 0.05 M sulfuric acid (H2SO4) aqueous solution were s tudied to explore the possibility of developing a Cr-saving stainless steel . Experimental results showed that the critical current density for passiva tion decreased with increasing Al and Si contents in Fe-8% Cr alloys. Combi ned addition of Al and Si decreased the current density more effectively. A ddition of Al had a slight effect in making the decay time longer. However addition of Si made the decay time exceedingly longer. The pitting potentia l in 3.5% sodium chloride (NaCl) aqueous solution moved in the noble direct ion with increasing Al and Si contents. Fe-8% Cr alloys containing Al and S i had the corrosion resistance that was equal to or greater than that of Fe -12% Cr stainless steel.