Surface Characterization of 1018 Carbon Steel in Borate Medium by in-situ Electrochemical Scanning Tunneling Microscopy

摘要

Microstructures of low carbon steel are ferrite (Fe-α) and pearlite (alternate mixture of Fe-α and Fe_3C) and each one has its own oxidation mechanism. These two phases were identified using in-situ electrochemical scanning tunneling microscopy (ECSTM). Real time images were obtained during the immersion of 1018 carbon steel probes in 0.642 M H_3BO_3 and 0.1 M NaOH, pH = 7.8. Two different corrosion mechanisms were identified and correlated with the observed surface changes.