Investigation of pitting corrosion of diamond-like carbon films using synchrotron-based spectromicroscopy

Corrosion behavior of diamond-like carbon (DLC) films was evaluated via potentiodynamic polarization in a 3.5 wt. % NaCl solution with pH 2 at room temperature. The polarization results elucidated that the corrosion resistance of the films was enhanced with the variation of the chemical compositions and film thicknesses. The use of the spectromicroscopy method in the investigation of the pitting corrosion was a success in this study. Formation of orbital mapping, bonding state, and composition of the DLC films at non-corrosion and corrosion areas indicate the different structures between DLC and graphite oxide. Also, the π* (C=C) and π* (C=O) bonding states were found to increase in the corrosion areas. This finding not only exhibited the increase of sp 2 content but also promoted the rise of oxygen atoms in corrosion zones. Consequently, the present results indicate that the synchrotron–based spectromicroscopy plays an important role in the characterization of the corrosion on DLC films.