Suitability evaluation of plasma ion beam sputtered TiN/TiOxNy multilayers on steel for bio implants

Layers of TiN/TiOxNy were coated onto 316L stainless steel substrates by plasma ion sputtering technique. The layers were sputtered with the arc current of 2.5 A and with an acceleration voltage of 1000 V, for a sputtering time of 120 min. The XPS survey spectra on the surface of coatings showed the characteristic Ti2p, N1s and O1s peaks at the corresponding binding energies. X-ray diffraction and TEM-SAD analysis showed mixed oxynitride phase with TiO2 and TiN for TiN/TiOxNy multilayer coatings. Cross sectional HRTEM analysis indicated the columnar structure of the coatings. Nanohardness value of 29 GPa was observed for mulilayered coatings. The electrochemical impedance measurements showed that the TiN/TiOxNy coatings on 316L SS exhibited superior corrosion resistance compared to the single layers and the bare 316L SS substrate in simulated bodily fluid solution. Platelet adhesion experiments were done to examine the interaction between blood and the materials in-vitro.