Structure and properties of Ti films deposited by dc magnetron sputtering, pulsed dc magnetron sputtering and cathodic arc evaporation

Nanocrystalline Ti films were deposited by continuous dc magnetron sputtering (dcMS), pulsed dc magnetron sputtering (PMS) and cathodic arc evaporation (CAE) separately. Their structures were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Mechanical and corrosion properties were studied via nanoindentation, microscratch test and electrochemical measurement. It was found that the dcMS Ti film exhibited a loose porous columnar structure with low film-substrate adhesion. Abundant macroparticles could be observed on the surface of CAE Ti film and it had a low film-substrate adhesion. On the other hand, the ion flux and ion energy of deposited particles in the PMS plasma were enhanced by increasing the average target power and decreasing the area of the sputter track as compared to those of the dcMS plasma. The high-power-density PMS Ti film exhibited a dense microstructure, fine grain size and smooth surface, with jointly enhanced corrosion resistance (corrosion current density of 0.04 μA · cm− 2) and film-substrate adhesion (critical load of 50 N).