Tribological investigations on MoS2-based nanolubricant for machine tool slideways

Abstract

The present study evaluates the tribological characteristics of molybdenum disulphide (MoS2)-based nanolubricant for its use in machine tool slideways. MoS2 nanoparticles were synthesized and physical characterization was carried out using scanning electron microscope and transmission electron microscope. The nanolubricants were prepared by adding various proportions of MoS2 nanoparticles in polyalphaolefin base oil with lecithin as dispersant. Friction, wear, and stick-slip characteristics of the nanolubricants were assessed using a pin-on-block reciprocating friction monitor simulating the actual loading conditions prevailing in machine tool slideways. Extreme pressure properties of the lubricants were determined using a four ball tester. The wear surfaces were analyzed using scanning electron microscopy and energy-dispersive spectroscopy. The results of the studies were compared with ISO VG 32, a conventional lubricant used in machine tool slideways, and it was found that the addition of MoS2 nanoparticles in polyalphaolefin base oil results in approximately 24% reduction in coefficient of friction and an increase in load-carrying capacity. The mechanism behind the improvement in tribological behavior of MoS2-based nanolubricant is most likely the formation of a thin, MoS2 tribofilm at the wear surface.