Effect of Substrate Pulse Bias Voltage on the Microstructure and Mechanical and Wear-resistant Properties of TiN/Cu Nanocomposite Films

TiN/Cu nanocomposite films were deposited on high-speed steel (HSS) substrates by axial magnetic field-enhanced arc ion plating (AMFE-AIP). The effects of substrate bias voltage on chemical composition, microstructure, mechanical and tribological properties of the films were investigated by X-ray photoelectrons spectroscopy (XPS), X-ray diffraction (XRD), nanoindentation and wear measurements, respectively. The results show that the Cu content increases first and then decreases with the increase of the pulse bias voltage, being a low value in the range of 1.3 at%∼2.1 at%. XRD results show that only the TiN phase appears in all the films, and no Cu phase is observed. The preferred orientation of the films changes significantly with the increasing pulse bias voltage. A maximum value of hardness of 36 GPa is obtained under a pulse bias voltage of −200 V, corresponding to the film containing 1.6 at% Cu. Compared to the pure TiN film, the Cu addition in TiN films significantly improves the wear resistance.