Preparation And Characterizing Of Solid Lubricative Nano Material MoS₂

Improving the antiwear and lubricating property of material has an important effect on the saving of resources and environmental protection. It not only satisfies the tendency of higher speed,heavier load and higher accuracy of the machine demanded by modern scientific technology,but also lengthens the life of the machine.In this paper, the synthesis, characterization and properties of solid lubricant MoS₂ with excellent environmental stability are studied. Two methods are used to prepare MoS₂ with different properties to satisfy its application under different conditions..The precursor MoS₃ was prepared by precipitation method with addition of poly ethylene glycol (PEG) as surface dispersant agent,and then MoS₂ particles were obtained from the desulfurization of MoS₃ in the mixed gases of H₂-N₂ at a certain temperature for a period of time. The as-prepared MoS₂ particles were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). The influences of surface dispersant agent, desulfurization temperature and time on MoS₂ are also discussed. The influence of the factors on MoS₃ yield is studied by single factor and orthogonal experiments, and the experimental conditions are optimized. It can be found that the addition of PEG could prevent the agglomeration of MoS₂ particles, and the average diameter of MoS₂ decreased with increasing the content of PEG. With the increase of desulphurizing time, the crystalline of MoS₂ is good, while the morphology of the particles is found to change from plate to sphericity. The as-prepared MoS₂ particles have good structural stability, physical and chemical properties. The average diameter of the granule particles is around 150nm. The particles with spherical structure, which can roll and glide freely, have excellent friction properties. So, they have potential applying foreground in the aero technology field.The surface modified molybdenum disulfide (MoS₂) nano particles were synthesized by using oleic acid as the modifying agent, CTAB as assistant agent, Hydrazine hydrate as reducer, and sodium molybdate, sodium sulfide, hydrochloric acid as raw materials. The experimental conditions are optimized by the orthogonal experiments. The obtained products were characterized by Infrared spectrum(IR) , Thermal Analysis System (TG-DTA), X-ray diffraction (XRD) and scanning electron microscope (SEM). The average diameter of the particles is 70-100nm. The results show the carboxyl groups of oleic acid were adsorbed in the surface of MoS₂ to form an organic-modified layer, which cause to strengthen affinity interaction between MoS₂ particles and organic solvents. Hence, the modified MoS₂ particles can be easily dispersed in many kinds of organic solvents, which lay the foundation for using as the additive of lubricating oil. The influence of calcination temperature on the particle size and morphology of MoS₂ is also investigated. The results indicate the MoS₂ modified by oleic acid has very good thermal stability. When the sample was calcined at 700℃for 2h, the MoS₂ partilce size is in the scope of nanometer grade, the crystalline of MoS₂ is much better, and the morphology of the particles is still spherical. Moreover, the surface modified mechanism of MoS₂ was proposed according to the experiment results.