Tribological Properties Of Molybdenum Disulfide Composite Particles Used As Lubricant Additives

Friction and wear of mechanical equipment not only lead to a large amount of energy consumption,but also lead to the failure or damage of mechanical equipment,reducing its service life.Lubrication can effectively reduce the friction and wear of the friction pairs.Nanoparticles as lubricating additives are commonly used to improve lubricating properties.However,nanoparticles tend to agglomerate during the sliding process,which affects their tribological properties.Because of the synergistic effect of the composite particles,the composite particles have better lubricating performance.Therefore,the tribological properties of molybdenum disulfide magnetic composite particles were studied in this work.In this thesis,Fe₃O₄ particles,MoS₂ nanoparticles and Fe₃O₄@MoS₂ nanoparticles were prepared by hydrothermal reaction.The three kinds of particles were dispersed in water and PAO4 base oil respectively for tribological tests.The tribological properties of these three kinds of nanoparticles were studied by means of analyzing the morphologies of frictional surfaces and the chemical valence states of the typical elements.The tribological properties of magnetic Fe₃O₄ nanoparticles,MoS₂ nanoparticles and Fe₃O₄@MoS₂ nanocomposite particles were studied as water based lubricant additives.The results show that the magnetic Fe₃O₄ particles can decrease the friction coefficient but increase the wear of the friction pair surface as the lubricating additive in deionized water system.When MoS₂ nanoparticles and Fe₃O₄@MoS₂ nanoparticles were used as lubricating additives in aqueous system,the friction coefficient and wear volume increased during the sliding process.Fe₃O₄ particles,MoS₂ nanoparticles and Fe₃O₄@MoS₂ nanoparticles were added to PAO4 base oil as additives.Unfortunately,no lubricating effect was observed for Fe₃O₄particles.However,both MoS₂ nanoparticles and Fe₃O₄@MoS₂ nanoparticles showed good lubricating effects.In addition,when Fe₃O₄@MoS₂ nanoparticles were used as lubricating additives,the lubricating effect was better,mainly because of the synergistic effect between Fe₃O₄ magnetic core and MoS₂ shell.It can be ascribed to the fact that the nano-composite particles are more easily adsorbed on the frictional interface,forming a sTablele adsorbed film and a solid tribo-film.