Structure and properties of DLC–MoS2 thin films synthesized by BTIBD method

• DLC–MoS2 films can be synthesized by a biased target ion beam deposition technique.
• Target bias voltage has great influence on structure and properties of DLC–MoS2.
• Comparing with DLC film, DLC–MoS2 thin film showed better tribological properties.

Diamond-like carbon (DLC)–MoS2 composite thin films were synthesized using a biased target ion beam deposition (BTIBD) technique in which MoS2 was produced by sputtering a MoS2 target using Ar ion beams while DLC was deposited by ion beam deposition with CH4 gas as carbon source. The structure and properties of the synthesized films were characterized by X-ray diffraction, X-ray absorption near edge structure (XANES), Raman spectroscopy, nanoindentation, ball-on-disk testing, and corrosion testing. The effect of MoS2 target bias voltage, ranging from −200 to −800 V, on the structure and properties of the DLC–MoS2 films was further investigated. The results showed that the hardness decreases from 9.1 GPa to 7 GPa, the Young׳s modulus decreases from 100 GPa to 78 GPa, the coefficient of friction (COF) increases from 0.02 to 0.17, and the specific wear rate coefficient (k) increases from 5×10−7 to 5×10−6 mm3 N−1 m−1, with increasing the biasing voltage from 200 V to 800 V. Also, the corrosion resistance of the DLC–MoS2 films decreased with the raise of biasing voltage. Comparing with the pure DLC and pure MoS2 films, the DLC–MoS2 films deposited at low biasing voltages showed better tribological properties including lower COF and k in ambient air environment.