Nanoindentation and corrosion studies of TiN/NiTi thin films for biomedical applications

The present study explored the in situ deposition of hard and adherent nanocrystalline TiN protective coating on NiTi thin films prepared by dc magnetron sputtering to improve the surface, mechanical and corrosion properties of NiTi thin films without sacrificing the phase transformation effect. The structural, electrical, and mechanical studies were performed on both pure NiTi and TiN/NiTi films and the results were compared. Nanoindentation studies were performed at temperatures of 297 K, 323 K, and 380 K to determine the hardness and reduced modulus. TiN/NiTi films were found to exhibit high hardness, high elastic modulus and thereby better wear resistance as compared to pure NiTi films. Further the application of TiN/NiTi films in the electrochemical sensing of dopamine, which has a critical physiological importance in Parkinson's disease has also been demonstrated. (C) 2009 Elsevier B.V. All rights reserved.