Variable corrosion behavior of a thick amorphous carbon coating in NaCl solution

Abstract

The present work investigates a thick amorphous multi-layer carbon coating fabricated by a plane hollow cathode plasma-enhanced chemical vapor deposition technique. The thick amorphous multi-layer carbon coating included a F–Si doped multi-layer structure, and a silicon interlayer which was able to reduce internal stress, improve the bonding and adhesion, and bridge the film and substrate. This work mainly discusses the cause of the variable corrosion behavior of the coating. Corrosion resistance was assessed by potentiodynamic polarization tests and electrochemical impedance spectroscopy (EIS) in 3.5 wt% NaCl solution. The results showed that the mild electrochemical reactions and corrosion product film had a significant effect on determining the variable corrosion behavior of the coating.