Effects of bias voltage on structure and properties of TiAl-doped a-C:H films prepared by 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. Effects of substrate bias voltage on structure and properties of the films, such as the surface morphology, hardness, chemical nature and bond types, were investigated 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 tribometer. SEM was utilized to analyze the wear scar on steel balls and debris after sliding on the deposited films under dry friction conditions. The results demonstrated that the film deposited at - 100 V exhibited low friction coefficient which is attributed to the easier formation of graphitized transfer layer.