Deposition and Characterization of Ti-Nb-C Films by DC Magnetron Sputtering

The films of the Ti-Nb-C system were deposited by direct current (DC) magnetron co-sputtering of elemental Ti, Nb, composite Ti+Nb, and graphite (C) targets. The microstructure, chemical bonds and mechanical properties of films were comparatively investigated. The X-ray diffraction (XRD) analysis revealed the presence of TiC and NbC crystallites in films deposited by co-sputtering of Ti/C and Nb/C targets. The peaks of the XRD spectra of the film obtained by co-spattering of the composite Ti+Nb and C targets are located in intermediate region between the corresponding peaks of the Ti-C and Nb-C films. The X-ray photoelectron spectroscopy (XPS) showed that the Ti-C and Nb-C bonds prevail in the deposited Ti-Nb-C films. It was suggested that the Ti-Nb-C films are nanocomposite and consist of the crystallites of the cubic TiC, NbC and TiC-NbC solid solutions surrounded by amorphous carbon-based matrix. The Knoop hardness of the Ti-Nb-C film is highest and reaches 36.8 GPa. The average friction coefficient determined before film delamination was lowest (0.17) in Ti-Nb-C film.