Influence ofmethane flow on the microstructure and properties of TiAl-doped a-C :H films deposited bymiddle frequency reactive magnetron sputtering

Hydrogenated TiAl-doped a-C :H films were deposited on Si substrates by middle frequency magnetron sputtering TiAl target in argon and methane gas mixture atmosphere. The surface morphology, hardness, chemical nature and bond types of the films were characterized by means of atomic force microscopy (AFM), XPS, Raman spectroscopy and nanoindentation. The friction and wear behaviors of the deposited films were characterized on an UMT-2MT test system. SEM was utilized to analyze the wear scar and debris on steel balls after sliding on the deposited films under dry friction conditions. The wear rate of the deposited films was calculated from traces of surface profiles taken across the wear track using an optical profile. The results demonstrated that the film deposited at 60 sccm methane flow exhibited higher hardness, as well as low friction coefficient and wear rate, which is attributed to the formation of a graphitized transfer layer.