Electrochemical Behavior of the Phase Structures of Stainless Steels in NaCl Solution

摘要

The authors have developed a measuring technique that can be used to investigate the electrochemical and corrosion behaviors of phase structures and micro areas in metals in situ and real-time. The electrochemical behaviors of various stainless steels and single phases of austenite, ferrite and martensite transformed by deformation in these various stainless steels in NaCl solution were successfully measured and investigated respectively. The free corrosion potential E_(corr), pitting potential E_b, free corrosion current density i_(corr), and the relationship between these parameters of various materials were measured by use of the measuring technique of phase electrochemistry. The results showed that the electrochemical behaviors of the single phases were obviously different from that of the relevant macro materials due to their high purity. Great difference existed between the electrochemical behaviors of different phases and of same phases of different stainless steels, as well of same phases before and after loading stress, which all will have significant effects on the corrosion process and mechanism. The electrochemical behaviors of the phase structures of stainless steels will have important effects on the initiation and propagation of localized corrosion.