Mechanical Properties and Biocompatibility of Ti-doped Diamond-like Carbon Films

A series of Ti/Ti-diamond-like carbon (Ti-DLC) films was deposited onto monocrystalline Si substrates by dual-magnetron sputtering. The mechanical properties, chemical composition, and microstructure of the films were investigated by Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), X-ray diffraction (XRD), and nanoindentation. The biocompatibility of the Ti-DLC films was evaluated via cell viability testing. The TiC phase was formed at a Ti content of 4.43 atom %, and the surface roughness gradually increased as the Ti content increased. Ti-DLC films with 17.13 atom % Ti exhibited superior adhesion strength and surface hardness. The optical densities (ODs) of the different Ti-DLC films were similar, indicating that the films exhibit biocompatibility regardless of the Ti content. Overall, doping DLC films with Ti provides a better film for medical applications, as it improves the mechanical properties, as evidenced by the elastic modulus, hardness, adhesion strength, and surface roughness of the coating, and maintains ideal biocompatibility.