Tribological properties of Fe–Ni-based composites with Ni-coated reduced graphene oxide–MoS 2

Abstract

Fe–Ni-based composites with Ni-coated reduced grapheme oxide (RGO)–MoS₂ were fabricated by powder metallurgy technique, and their morphology, phase composition, and tribological properties at different temperatures were investigated systematically. Results showed that Fe–Ni-based composite with Ni-coated RGO–MoS₂ possessed much more uniform and denser microstructure, and higher hardness than that with RGO–MoS₂. Furthermore, Ni-coated RGO–MoS₂ additive greatly allowed increasing the friction-reducing and wear-resistant properties, due to the reinforcing and lubricating effect new phase (Fe₃W₃C, Cr_xS_{1+ x} , etc.) and the improvement on interfacial compatibility between Ni-coated RGO–MoS₂ and Fe–Ni matrix. In particular, as the content of Ni-coated RGO–MoS₂ was 5 wt%, the friction coefficient and wear rate of the corresponding composite was decreased nearly 50% and 75%, respectively. More importantly, Ni-coated RGO–MoS₂ reinforced composite kept excellent tribological properties at elevated temperature. Its friction coefficient decreased firstly with the increased temperature from 25℃ to 400℃, then increased slightly when the temperature increased to 600℃. Besides, the wear rate was only 0.73–0.9 × 10⁻⁴ mm³/Nm during the whole temperature range. This suggested that Ni-coated RGO–MoS₂ was a promising additive of metallic-based composites suitable for high-temperature sliding condition.