Abstract: Diamond-like carbon (DLC) film was deposited via high power impulse magnetron sputtering (HiPIMS) technology at bias voltage range between 0 to -300 V. The microstructure of the film was characterized by using Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM). The mechanical properties of the film were investigated through the utilization of nanoindentation, scratch and friction and wear tests. The results demonstrate that with the increase of negative bias voltage, the I_D/I_G value of DLC film initially decreases and then increases, the full width at half maximum of G peak(FWHM(G)) initially increases and then decreases, and the I_D/I_G value of the film prepared with bias voltage of -200 V is the smallest, the FWHM(G) is the largest, and the sp³ bond content is the highest, reaching 58.0%. The section morphology of the DLC film at different bias voltages exhibits no discernible columnar structure, particularly at bias voltages of -200 V or -300 V, where the film displays a dense glass-like structure. The hardness (H), relative elastic modulus (E^*), H/E^*, H³/E^*2 and sp³ contents of the film under different bias voltage are essentially comparable, at bias voltage of -200 V, the film exhibits the optimal comprehensive mechanical properties, with hardness and relative elastic modulus of 23.91 GPa and 260.45 GPa, respectively. The values of H/E^* and H³/E^*2 are 0.0918 and 0.2016 GPa, respectively. The scratch morphologies of the DLC films at different bias voltages demonstrate that films prepared with -100 V and -200 V exhibit excellent adhension strength, with a critical load (L_c2) of at least 80 N. Additionally, the friction tests indicate that the DLC films possess excellent tribological properties. In particular, the film deposited at -200 V exhibits the lowest average friction coefficient(0.09) and the lowest wear rate (5.75×10^-16 m³/(N·m)).

Key words: high power impulse magnetron sputtering (HiPIMS), diamond-like carbon film, substrate bias voltage, microstructure, mechanical properties