Friction and wear properties of carbon-ion implanted titanium nitride films

TiN films were deposited by ion plating on high speed tool steel substrates, and implanted by carbon ions with fluences up to 5×1017 ions/cm2 and with energies ranging from 50 to 150 keV. Friction and wear tests were carried out by a pin-on-disk tribometer with stainless steel balls as a counter material. The surface layers of TiN films modified by the carbon-ion implantation were characterized by X-ray diffraction (XRD) for crystal structure identification and X-ray photoelectron spectroscopy (XPS) for chemical composition analysis. The carbon-ion implantation reduced the friction coefficient of the TiN films against the stainless steel balls, and also the wear volume of the steel balls. The duration of the low friction coefficient was extended with increasing carbon dose. Adhesion of the counter material could be prevented by the carbon-ion implantation into TiN film, leading to a drastic decrease of the friction coefficient. The tribological properties of the carbon-implanted TiN films can be controlled by carbon dose and ion energy: wear rate and frictional behavior of the TiN coating can be reduced.