Enhancement of biocompatibility of metal implants by nanoscale tiN/NbN multilayer coatings.

Titanium nitride (TiN)/niobium nitride (NbN) nanostructured multilayer coatings were prepared by DC reactive magnetron sputtering method using the combination of a titanium and niobium target and an Ar-N2 mixture discharge gas on to 316L stainless steel substrates. The coatings showed a polycrystalline structure with (111) for TiN and (101) for NbN preferential growth. Raman spectroscopy measurements on the multilayer films exhibited the characteristic peaks at 212, 303, 458 and 578 cm-1. A higher hardness of 38 GPa was observed for TiN/NbN coatings. Electrochemical polarization tests were performed in simulated biological fluid solutions at 37 degreesC in order to determine and compare the corrosion behavior of the coated and uncoated 316L SS substrates. The TiN/NbN multilayer coatings could improve the corrosion resistance of 316L SS substrate. The bacterial culture experiments were performed and the bacteria treated samples were examined by epi fluorescence microscope measurements.