Electrochemical corrosion behavior of amorphous carbon nitride thin films

摘要

The corrosion behavior along with biocompatibility and mechanical properties plays an important role in determining of biomedical implants feasibility. Diamond-like carbon seems to be the promising material in which all these three requirements can be achieved. In this study nitrogen doped amorphous carbon (a-C:N) films were deposited on silicon and medical CoCrMo alloy substrates by vacuum glow discharge sputtering technique using different deposition conditions from graphite target. Potentiodynamic polarization tests were employed to assess the corrosion performances of the films at room temperature in 0.89 wt. % NaCl solution. The influence of substrate bias on the electrochemical corrosion behavior was investigated. The highest value off E _(corr) for CoCrMo substrate was measured on the coating deposited with substrate bias around -0.6 kV. The shift of E _(corr) to more positive values was about 350 mV.