Electrostatically Self-Assembled Magnetic Nanoparticles for High-Temperature Resistant and Friction-Controlled Lubrication System.

ABSTRACT

Magnetic-responsive surfactants are considered promising smart lubricating materials due to their significant stimulation response to applied magnetic fields. In this study, four magneto-responsive surfactants are successfully fabricated and encapsulated on the surface of molybdenum disulfide nanosheets (MoS2@C18H37N+(CH3)3[XCl3Br]-, X = Fe, Ce, Gd, and Ho) as base-oil components using electrostatic self-assembly, thereby constructing a multi-functional magnetic lubrication system (MoS2@STAX). Magnetorheological measurements confirm the remarkable responsiveness of MoS2@STACe lubricants at high shear rates and applied magnetic fields, which is further corroborated by the constant proximity of the magnet. The formation of dense carbon and tribo-chemical films between the friction interfaces at elevated temperatures is the primary factor contributing to the significant reduction in frictional wear. Notably, the magnetic lubricant demonstrates a pronounced response behavior when subjected to an applied magnetic field in the ceramic tribopair, even at lower magnetic fields. This work presents concepts for the development of high-temperature resistant and tunable lubrication additives by designing the material structure and controlling the magnetic stimulation.