Preparation And Tribological Properties Of Two Typical Two-dimensional Materials

Two-dimensional materials?graphene,fluorographene,molybdenum disulfide,etc.?have attracted considerable attention in recent years.Among them,fluorographene?FG?is a derivative of graphene,and graphene-like molybdenum disulfide?MoS₂?is composed of a monolayer or few layers of MoS₂.Two-dimensional materials is regarded as the important candidate materials for advanced technological applications in interface science,nanometer scale device,lubricant materials and other fields because of their unique structures and properties different from traditional bulk material,such as their distinctive mechanical,optical,electronic,and magnetic properties.The main research contents of this thesis are focused on the preparation and tribological properties of FG and graphene-like MoS₂ nanosheets.The main contents and conclusions are as follows.1.FG and MoS₂ nanosheets were respectively prepared by wet ball-milling fluorinated graphite and MoS₂ powders.We intermingle raw material with polyvinylpyrrolidone?PVP?to improve the quality of the nanosheets for it is easy to agglomerate.FG and MoS₂ nanosheets can be obtained at the milling speed of 300 r/min.2.The as-prepared FG and MoS₂ nanosheets were dispersed respectively in the ethanol to investigate their tribological properties.The results demonstrated that the FG and MoS₂ nanosheets could enhance the tribological property of ethanol as the effective lubricant additive.3.The as-prepared FG and MoS₂ nanosheets were further used as lubricant additives in the base oil?PAO-8?to investigate their tribological properties.The results demonstrated that the introduction of a small amount of FG?0.30 mg/ml?and MoS₂ nanosheets?0.20 mg/ml?into the base oil could reduce wear rate drastically to 34% and 50% of those of the base oil,respectively.The possible mechanism is: the nanosheets form a continuous,compact and firm physical film under the shear force,which not only bears the load of the steel ball but also separates the rubbing faces and prevents them form direct contact,so the wear and friction decrease.