Electrochemicral impedance spectroscopy (EIS) was used to evaluate the
corrosion performance of four high chromium stainless steels and Grade 2 titanium in flowing Arabian Gulf natural seawater. The EIS provided information concerning the changes to the interracial impedance as a function of exposure time for these alloys. The impedance spectra for all the alloys showed slight changes at the low frequency region over the exposure period. The open-circuit potentials (OCP) of these alloys were also monitored as a function of exposure time. The stainless steel alloys
efilbited slight fluctuation in potential around the initial exposure potential.
However, Grade 2 titanium initial potential was more active and then gradually shifted towards the noble direction. The linear polarization resistance (LPR) method indicated that Grade 2 titanium exhibited the lowest corrosion rate with respect to the stainless steel alloys. The results of the EIS analysis and OCP indicated that Grade 2 titanium performed better than the four high chromium stainless steel alloys.
Key Words: Electrochemical impedance, Open-Circuit Potential,
Seawater, Stainless Steels, Titanium.