Corrosion resistance of UNS S31603 stainless steel in the Gulf of Mexico

The effect of exposure time, in the Gulf of Mexico, on UNS S31603 stainless steel pitting corrosion resistance, was studied for 30 days using both open circuit potential and potentiodynamic polarization techniques. Biofilm formation and corrosion attack were subsequently observed using scanning electron microscope and atomic force microscopy. It was found that microorganisms colonizing the steel specimen's surface during the first three days of testing modified the OCP towards electropositive values, increasing the risk of pitting corrosion. It was also observed that the SS specimens were most sensitive to pitting corrosion within the first fifteen days of exposure in seawater; this sensitivity decreased during the last week, probably due to a decay in the biological activity and better behaviour of the passive film.