Nanosized molybdenum disulphide as effective additive for lubricant grease: synthesis, rheological and tribological characterization

MoS2@oleylamine nanosheets were successfully synthesized by a novel wet chemistry approach. Two dispersions of nanosheets in Calcium and Lithium based greases were investigated with respect to rheological and tribological properties. The inclusion of the MoS2 nanosheets in the in Calcium and Lithium based greases determines slightly higher values of the elastic response and of the complex viscosity of the based greases.The tribological results show a marked decreasing in friction coefficient both in boundary and mixed lubrication regimes achievable through MoS2 nanosheets dispersion, with average reduction for Calcium and Lithium grease around 35%. The anti-wear property of MoS2 nanosheets as additive for Calcium and Lithium greases has been also clearly exhibited in both the above lubrication regimes, leading to an average level of 30% decreasing on the scar diameter measured on the steel ball worn surface.