Copper films deposited by arc ion plating at low temperatures exhibiting excellent antiwear behaviour

Cu films were prepared by arc ion plating (AIP) at low temperature (T _s) and investigated by X-ray diffraction, field emission scanning electron microscope atomic force microscopy, transmission electron microscope, etc. It is found that low Ts (≤ 221 K) can refine the crystallite size of the Cu films and leads to compact and smooth surface structure. Further decreasing T_s to 135 K makes the inter-grain gaps turn bigger. The wear behaviours of the Cu films in vacuum were characterized using a ball-on-disk tribometer. The results show that the Cu films deposited at the T_s range of 135-221 K have better wear resistance, and the wear rates are two to three orders lower than that of the film deposited at room temperature. The compact and dense arrangement of nanoscale crystallites significantly contributes to the improved film-substrate adhesion and so the excellent antiwear behaviour.