Electrochemical studies on nitrogen ion implanted Ti6Al4V alloy

Nitrogen ion implantation on a Ti6Al4V alloy with 70KeV energy was carried out at different doses ranging from 5 × 10¹⁵ to 2.5 × 10¹⁷ions/cm². The implanted samples were subjected to open circuit potential/time measurement and cyclic polarization studies to evolve the optimum dose which can give good corrosion resistance in a simulated body fluid condition. The results show that there was an increase in corrosion resistance with increased doses up to 7 × 10¹⁶ions/cm², beyond which it started to decrease. The stability of the passive film at a higher potential was assessed by potentiotransient techniques after impressing a constant potential of 1.5V for three hours. The results of the investigation indicate that nitrogen ion implantation can be used as a viable method to improve the corrosion resistance of orthopaedic implant devices made of Ti6Al4V alloy. The nature of the stable passive film and its influence on corrosion resistance are discussed in this paper.