THE STUDY OF ELECTROCHEMICAL BEHAVIOR OF TiN COATED STAINLESS STEEL IN ARTIFICIAL BODY FLUID

Stainless steel 316L is commonly used as a biomedical material in different implants like hip and knee joints. Stainless steel 316L has good bulk properties however its surface properties need to be modified by surface treatments for certain applications. Human body environment plays an important role in implant’s corrosion especially when it comes in contact with body fluid. To overcome this problem, thin PVD coatings are commonly used on metallic implants. In this study, stainless steel 316L samples were coated with Titanium Nitride (TiN) coating by physical vapor deposition Sputtering method. Corrosion behavior of TiN coated and uncoated stainless steel 316L were assessed in artificial human body fluid by Open Circuit Potential (OCP) and Electrochemical Impedance Spectroscopy (EIS). The results of this study revealed that corrosion resistance for TiN coated substrate is higher than uncoated in the initial 24 hours. After 20 days immersion, the resistance of TiN coated substrate is decreased but remained higher than uncoated substrate. The corrosion surfaces were analyzed by Scanning Electron Microscopy (SEM). Key words: PVD coatings, TiN, Biomedical material, Corrosion, Open circuit Potential (OCP), Electrochemical Impedance Spectroscopy (EIS)