Corrosion behavior of DLC-coated NiTi alloys in the presence of serum proteins

Diamond-like carbon (DLC) coatings was deposited on NiTi substrates by arc enhanced magnetic sputtering (AEMS) system. The effect of serum proteins, bovine serum albumin (BSA) and fibrinogen (Fib) on the corrosion behavior of DLC-coated NiTi alloys in phosphate buffer saline (PBS) solution at 37°C was investigated using open circuit potential (OCP), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization measurements. The results showed that DLC coatings could enhance the corrosion resistance of NiTi alloys, especially in the presence of BSA, which could move the OCP to positive direction, increase the polarization resistance, lower the corrosion current density and enhance the breakdown potential. The presence of fibrinogen showed the similar effect but less notable than BSA. Finally, the mechanism leading to these results were discussed.