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

Uniform and adherent diamond-like carbon (DLC) coatings are deposited on NiTi alloy by arc enhanced magnetron sputtering (AEMS). The effects of serum proteins, bovine serum albumin (BSA) and fibrinogen (Fib) on the corrosion behavior of DLC-coated NiTi alloy in phosphate buffer saline (PBS) solution are investigated at 37 °C using open circuit potential (OCP), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization measurements. The results show that DLC coatings, which enhance the corrosion resistance of the NiTi alloy especially in the presence of BSA, move the OCP to the positive direction, increase the polarization resistance, lower the corrosion current density, and enhance the breakdown potential. The presence of fibrinogen shows the similar effect but less notable than BSA. The associated mechanism is also discussed.