Electrochemical Corrosion Behavior of AISI Type 304 Stainless Steel in Nitric Acid Media

The effect of temperature and concentration of HNO3 on the corrosion behavior of 304 stainless steel(SS) was studied by potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS). The results indicated that the electrochemical impedance spectroscopy (EIS) of 304 SS presented capacitance loop with impedance approaching to 104 Ω·cm2 at passive potential, indicating the formation of a compact passivation film. With the increase of temperature, the impedance and phase angle decreased, localized corrosion was accelerated severely. High temperatures and high concentrations will promote the dissolution of the passive film, thereby accelerating the corrosion of 304 SS in nitric acid.